title: Io (moon)

text: Jupiter's magnetic field, which Io crosses, couples Io's atmosphere and neutral cloud to Jupiter's polar upper atmosphere by generating an electric current known as the Io flux tube. This current produces an auroral glow in Jupiter's polar regions known as the Io footprint, as well as aurorae in Io's atmosphere. Particles from this auroral interaction darken the Jovian polar regions at visible wavelengths. The location of Io and its auroral footprint with respect to Earth and Jupiter has a strong influence on Jovian radio emissions from our vantage point: when Io is visible, radio signals from Jupiter increase considerably. The "Juno" mission, currently in orbit around Jupiter, should help to shed light on these processes. The Jovian magnetic field lines that do get past Io's ionosphere also induce an electric current, which in turn creates an induced magnetic field within Io's interior. Io's induced magnetic field is thought to be generated within a partially molten, silicate magma ocean 50 kilometers beneath Io's surface. Similar induced fields were found at the other Galilean satellites by "Galileo", possibly generated within liquid water oceans in the interiors of those moons.


title: Io (moon)

text: Io is slightly larger than Earth's Moon. It has a mean radius of (about 5% greater than the Moon's) and a mass of 8.9319 kg (about 21% greater than the Moon's). It is a slight ellipsoid in shape, with its longest axis directed toward Jupiter. Among the Galilean satellites, in both mass and volume, Io ranks behind Ganymede and Callisto but ahead of Europa.


title: Io (moon)

text: Composed primarily of silicate rock and iron, Io and Europa are closer in bulk composition to the terrestrial planets than to other satellites in the outer Solar System, which are mostly composed of a mix of water ice and silicates. Io has a density of , the highest of any regular moon in the Solar System; significantly higher than the other Galilean satellites (Ganymede and Callisto in particular, whose densities are around ) and slightly higher (~5.5%) than the Moon's and Europa's . Models based on the "Voyager" and "Galileo" measurements of Io's mass, radius, and quadrupole gravitational coefficients (numerical values related to how mass is distributed within an object) suggest that its interior is differentiated between a silicate-rich crust and mantle and an iron- or iron-sulfide-rich core. Io's metallic core makes up approximately 20% of its mass. Depending on the amount of sulfur in the core, the core has a radius between if it is composed almost entirely of iron, or between for a core consisting of a mix of iron and sulfur. "Galileo" magnetometer failed to detect an internal, intrinsic magnetic field at Io, suggesting that the core is not convecting.


title: Io (moon)

text: Modeling of Io's interior composition suggests that the mantle is composed of at least 75% of the magnesium-rich mineral forsterite, and has a bulk composition similar to that of L-chondrite and LL-chondrite meteorites, with higher iron content (compared to silicon) than the Moon or Earth, but lower than Mars. To support the heat flow observed on Io, 10–20% of Io's mantle may be molten, though regions where high-temperature volcanism has been observed may have higher melt fractions. However, re-analysis of "Galileo" magnetometer data in 2009 revealed the presence of an induced magnetic field at Io, requiring a magma ocean below the surface. Further analysis published in 2011 provided direct evidence of such an ocean. This layer is estimated to be 50 km thick and to make up about 10% of Io's mantle. It is estimated that the temperature in the magma ocean reaches 1,200 °C. It is not known if the 10–20% partial melting percentage for Io's mantle is consistent with the requirement for a significant amount of molten silicates in this possible magma ocean. The lithosphere of Io, composed of basalt and sulfur deposited by Io's extensive volcanism, is at least thick, and likely less than thick.


title: Io (moon)

text: Unlike Earth and the Moon, Io's main source of internal heat comes from tidal dissipation rather than radioactive isotope decay, the result of Io's orbital resonance with Europa and Ganymede. Such heating is dependent on Io's distance from Jupiter, its orbital eccentricity, the composition of its interior, and its physical state. Its Laplace resonance with Europa and Ganymede maintains Io's eccentricity and prevents tidal dissipation within Io from circularizing its orbit. The resonant orbit also helps to maintain Io's distance from Jupiter; otherwise tides raised on Jupiter would cause Io to slowly spiral outward from its parent planet. The tidal forces experienced by Io are about 20,000 times stronger than the tidal forces Earth experiences due to the Moon, and the vertical differences in its tidal bulge, between the times Io is at periapsis and apoapsis in its orbit, could be as much as . The friction or tidal dissipation produced in Io's interior due to this varying tidal pull, which, without the resonant orbit, would have gone into circularizing Io's orbit instead, creates significant tidal heating within Io's interior, melting a significant amount of Io's mantle and core. The amount of energy produced is up to 200 times greater than that produced solely from radioactive decay. This heat is released in the form of volcanic activity, generating its observed high heat flow (global total: 0.6 to 1.6×10 W). Models of its orbit suggest that the amount of tidal heating within Io changes with time; however, the current amount of tidal dissipation is consistent with the observed heat flow. Models of tidal heating and convection have not found consistent planetary viscosity profiles that simultaneously match tidal energy dissipation and mantle convection of heat to the surface.


title: Io (moon)

text: Although there is general agreement that the origin of the heat as manifested in Io's many volcanoes is tidal heating from the pull of gravity from Jupiter and its moon Europa, the volcanoes are not in the positions predicted with tidal heating. They are shifted 30 to 60 degrees to the east. A study published by Tyler "et al." (2015) suggests that this eastern shift may be caused by an ocean of molten rock under the surface. The movement of this magma would generate extra heat through friction due to its viscosity. The study's authors believe that this subsurface ocean is a mixture of molten and solid rock.


title: Io (moon)

text: Other moons in the Solar System are also tidally heated, and they too may generate additional heat through the friction of subsurface magma or water oceans. This ability to generate heat in a subsurface ocean increases the chance of life on bodies like Europa and Enceladus.


title: Io (moon)

text: Based on their experience with the ancient surfaces of the Moon, Mars, and Mercury, scientists expected to see numerous impact craters in "Voyager 1" first images of Io. The density of impact craters across Io's surface would have given clues to Io's age. However, they were surprised to discover that the surface was almost completely lacking in impact craters, but was instead covered in smooth plains dotted with tall mountains, pits of various shapes and sizes, and volcanic lava flows. Compared to most worlds observed to that point, Io's surface was covered in a variety of colorful materials (leading Io to be compared to a rotten orange or to pizza) from various sulfurous compounds. The lack of impact craters indicated that Io's surface is geologically young, like the terrestrial surface; volcanic materials continuously bury craters as they are produced. This result was spectacularly confirmed as at least nine active volcanoes were observed by "Voyager 1".


title: Io (moon)

text: Io's colorful appearance is the result of materials deposited by its extensive volcanism, including silicates (such as orthopyroxene), sulfur, and sulfur dioxide. Sulfur dioxide frost is ubiquitous across the surface of Io, forming large regions covered in white or grey materials. Sulfur is also seen in many places across Io, forming yellow to yellow-green regions. Sulfur deposited in the mid-latitude and polar regions is often damaged by radiation, breaking up the normally stable cyclic 8-chain sulfur. This radiation damage produces Io's red-brown polar regions.


title: Io (moon)

text: Explosive volcanism, often taking the form of umbrella-shaped plumes, paints the surface with sulfurous and silicate materials. Plume deposits on Io are often colored red or white depending on the amount of sulfur and sulfur dioxide in the plume. Generally, plumes formed at volcanic vents from degassing lava contain a greater amount of , producing a red "fan" deposit, or in extreme cases, large (often reaching beyond from the central vent) red rings. A prominent example of a red-ring plume deposit is located at Pele. These red deposits consist primarily of sulfur (generally 3- and 4-chain molecular sulfur), sulfur dioxide, and perhaps sulfuryl chloride. Plumes formed at the margins of silicate lava flows (through the interaction of lava and pre-existing deposits of sulfur and sulfur dioxide) produce white or gray deposits.


title: Io (moon)

text: Compositional mapping and Io's high density suggest that Io contains little to no water, though small pockets of water ice or hydrated minerals have been tentatively identified, most notably on the northwest flank of the mountain Gish Bar Mons. Io has the least amount of water of any known body in the Solar System. This lack of water is likely due to Jupiter being hot enough early in the evolution of the Solar System to drive off volatile materials like water in the vicinity of Io, but not hot enough to do so farther out.


title: Io (moon)

text: The tidal heating produced by Io's forced orbital eccentricity has made it the most volcanically active world in the Solar System, with hundreds of volcanic centres and extensive lava flows. During a major eruption, lava flows tens or even hundreds of kilometres long can be produced, consisting mostly of basalt silicate lavas with either mafic or ultramafic (magnesium-rich) compositions. As a by-product of this activity, sulfur, sulfur dioxide gas and silicate pyroclastic material (like ash) are blown up to into space, producing large, umbrella-shaped plumes, painting the surrounding terrain in red, black, and white, and providing material for Io's patchy atmosphere and Jupiter's extensive magnetosphere.


title: Io (moon)

text: Io's surface is dotted with volcanic depressions known as "paterae" which generally have flat floors bounded by steep walls. These features resemble terrestrial calderas, but it is unknown if they are produced through collapse over an emptied lava chamber like their terrestrial cousins. One hypothesis suggests that these features are produced through the exhumation of volcanic sills, and the overlying material is either blasted out or integrated into the sill. Examples of paterae in various stages of exhumation have been mapped using "Galileo" images of the Chaac-Camaxtli region. Unlike similar features on Earth and Mars, these depressions generally do not lie at the peak of shield volcanoes and are normally larger, with an average diameter of , the largest being Loki Patera at . Loki is also consistently the strongest volcano on Io, contributing on average 25% of Io's global heat output. Whatever the formation mechanism, the morphology and distribution of many paterae suggest that these features are structurally controlled, with at least half bounded by faults or mountains. These features are often the site of volcanic eruptions, either from lava flows spreading across the floors of the paterae, as at an eruption at Gish Bar Patera in 2001, or in the form of a lava lake. Lava lakes on Io either have a continuously overturning lava crust, such as at Pele, or an episodically overturning crust, such as at Loki.


title: Io (moon)

text: Lava flows represent another major volcanic terrain on Io. Magma erupts onto the surface from vents on the floor of paterae or on the plains from fissures, producing inflated, compound lava flows similar to those seen at Kilauea in Hawaii. Images from the "Galileo" spacecraft revealed that many of Io's major lava flows, like those at Prometheus and Amirani, are produced by the build-up of small breakouts of lava flows on top of older flows. Larger outbreaks of lava have also been observed on Io. For example, the leading edge of the Prometheus flow moved between "Voyager" in 1979 and the first "Galileo" observations in 1996. A major eruption in 1997 produced more than of fresh lava and flooded the floor of the adjacent Pillan Patera.


title: Io (moon)

text: Analysis of the "Voyager" images led scientists to believe that these flows were composed mostly of various compounds of molten sulfur. However, subsequent Earth-based infrared studies and measurements from the "Galileo" spacecraft indicate that these flows are composed of basaltic lava with mafic to ultramafic compositions. This hypothesis is based on temperature measurements of Io's "hotspots", or thermal-emission locations, which suggest temperatures of at least 1,300 K and some as high as 1,600 K. Initial estimates suggesting eruption temperatures approaching 2,000 K have since proven to be overestimates because the wrong thermal models were used to model the temperatures.


title: Io (moon)

text: The discovery of plumes at the volcanoes Pele and Loki were the first sign that Io is geologically active. Generally, these plumes are formed when volatiles like sulfur and sulfur dioxide are ejected skyward from Io's volcanoes at speeds reaching , creating umbrella-shaped clouds of gas and dust. Additional material that might be found in these volcanic plumes include sodium, potassium, and chlorine. These plumes appear to be formed in one of two ways. Io's largest plumes, such as those emitted by Pele, are created when dissolved sulfur and sulfur dioxide gas are released from erupting magma at volcanic vents or lava lakes, often dragging silicate pyroclastic material with them. These plumes form red (from the short-chain sulfur) and black (from the silicate pyroclastics) deposits on the surface. Plumes formed in this manner are among the largest observed at Io, forming red rings more than in diameter. Examples of this plume type include Pele, Tvashtar, and Dazhbog. Another type of plume is produced when encroaching lava flows vaporize underlying sulfur dioxide frost, sending the sulfur skyward. This type of plume often forms bright circular deposits consisting of sulfur dioxide. These plumes are often less than tall, and are among the most long-lived plumes on Io. Examples include Prometheus, Amirani, and Masubi. The erupted sulfurous compounds are concentrated in the upper crust from a decrease in sulfur solubility at greater depths in Io's lithosphere and can be a determinant for the eruption style of a hot spot.


title: Io (moon)

text: Io has 100 to 150 mountains. These structures average in height and reach a maximum of at South "Boösaule Montes". Mountains often appear as large (the average mountain is long), isolated structures with no apparent global tectonic patterns outlined, in contrast to the case on Earth. To support the tremendous topography observed at these mountains requires compositions consisting mostly of silicate rock, as opposed to sulfur.


title: Io (moon)

text: Despite the extensive volcanism that gives Io its distinctive appearance, nearly all its mountains are tectonic structures, and are not produced by volcanoes. Instead, most Ionian mountains form as the result of compressive stresses on the base of the lithosphere, which uplift and often tilt chunks of Io's crust through thrust faulting. The compressive stresses leading to mountain formation are the result of subsidence from the continuous burial of volcanic materials. The global distribution of mountains appears to be opposite that of volcanic structures; mountains dominate areas with fewer volcanoes and vice versa. This suggests large-scale regions in Io's lithosphere where compression (supportive of mountain formation) and extension (supportive of patera formation) dominate. Locally, however, mountains and paterae often abut one another, suggesting that magma often exploits faults formed during mountain formation to reach the surface.


title: Io (moon)

text: Mountains on Io (generally, structures rising above the surrounding plains) have a variety of morphologies. Plateaus are most common. These structures resemble large, flat-topped mesas with rugged surfaces. Other mountains appear to be tilted crustal blocks, with a shallow slope from the formerly flat surface and a steep slope consisting of formerly sub-surface materials uplifted by compressive stresses. Both types of mountains often have steep scarps along one or more margins. Only a handful of mountains on Io appear to have a volcanic origin. These mountains resemble small shield volcanoes, with steep slopes (6–7°) near a small, central caldera and shallow slopes along their margins. These volcanic mountains are often smaller than the average mountain on Io, averaging only in height and wide. Other shield volcanoes with much shallower slopes are inferred from the morphology of several of Io's volcanoes, where thin flows radiate out from a central patera, such as at Ra Patera.


title: Io (moon)

text: Nearly all mountains appear to be in some stage of degradation. Large landslide deposits are common at the base of Ionian mountains, suggesting that mass wasting is the primary form of degradation. Scalloped margins are common among Io's mesas and plateaus, the result of sulfur dioxide sapping from Io's crust, producing zones of weakness along mountain margins.


title: Io (moon)

text: Io has an extremely thin atmosphere consisting mainly of sulfur dioxide (), with minor constituents including sulfur monoxide (), sodium chloride (), and atomic sulfur and oxygen. The atmosphere has significant variations in density and temperature with time of day, latitude, volcanic activity, and surface frost abundance. The maximum atmospheric pressure on Io ranges from 3.3 to 3 pascals (Pa) or 0.3 to 3 nbar, spatially seen on Io's anti-Jupiter hemisphere and along the equator, and temporally in the early afternoon when the temperature of surface frost peaks. Localized peaks at volcanic plumes have also been seen, with pressures of 5 to 40  Pa (5 to 40 nbar). Io's atmospheric pressure is lowest on Io's night side, where the pressure dips to 0.1 to 1 Pa (0.0001 to 0.001 nbar). Io's atmospheric temperature ranges from the temperature of the surface at low altitudes, where sulfur dioxide is in vapor pressure equilibrium with frost on the surface, to 1,800 K at higher altitudes where the lower atmospheric density permits heating from plasma in the Io plasma torus and from Joule heating from the Io flux tube. The low pressure limits the atmosphere's effect on the surface, except for temporarily redistributing sulfur dioxide from frost-rich to frost-poor areas, and to expand the size of plume deposit rings when plume material re-enters the thicker dayside atmosphere. The thin Ionian atmosphere also means any future landing probes sent to investigate Io will not need to be encased in an aeroshell-style heatshield, but instead require retrothrusters for a soft landing. The thin atmosphere also necessitates a rugged lander capable of enduring the strong Jovian radiation, which a thicker atmosphere would attenuate.


title: Io (moon)

text: Gas in Io's atmosphere is stripped by Jupiter's magnetosphere, escaping to either the neutral cloud that surrounds Io, or the Io plasma torus, a ring of ionized particles that shares Io's orbit but co-rotates with the magnetosphere of Jupiter. Approximately one ton of material is removed from the atmosphere every second through this process so that it must be constantly replenished. The most dramatic source of are volcanic plumes, which pump kg of sulfur dioxide per second into Io's atmosphere on average, though most of this condenses back onto the surface. Much of the sulfur dioxide in Io's atmosphere is sustained by sunlight-driven sublimation of frozen on the surface. The day-side atmosphere is largely confined to within 40° of the equator, where the surface is warmest and most active volcanic plumes reside. A sublimation-driven atmosphere is also consistent with observations that Io's atmosphere is densest over the anti-Jupiter hemisphere, where frost is most abundant, and is densest when Io is closer to the Sun. However, some contributions from volcanic plumes are required as the highest observed densities have been seen near volcanic vents. Because the density of sulfur dioxide in the atmosphere is tied directly to surface temperature, Io's atmosphere partially collapses at night, or when Io is in the shadow of Jupiter (with an ~80% drop in column density). The collapse during eclipse is limited somewhat by the formation of a diffusion layer of sulfur monoxide in the lowest portion of the atmosphere, but the atmosphere pressure of Io's nightside atmosphere is two to four orders of magnitude less than at its peak just past noon. The minor constituents of Io's atmosphere, such as , , , and derive either from: direct volcanic outgassing; photodissociation, or chemical breakdown caused by solar ultraviolet radiation, from ; or the sputtering of surface deposits by charged particles from Jupiter's magnetosphere.


title: Io (moon)

text: Various researchers have proposed that the atmosphere of Io freezes onto the surface when it passes into the shadow of Jupiter. Evidence for this is a "post-eclipse brightening", where the moon sometimes appears a bit brighter as if covered with frost immediately after eclipse. After about 15 minutes the brightness returns to normal, presumably because the frost has disappeared through sublimation. Besides being seen through ground-based telescopes, post-eclipse brightening was found in near-infrared wavelengths using an instrument aboard the "Cassini" spacecraft. Further support for this idea came in 2013 when the Gemini Observatory was used to directly measure the collapse of Io's atmosphere during, and its reformation after, eclipse with Jupiter.


title: Io (moon)

text: High-resolution images of Io acquired when Io is experiencing an eclipse reveal an aurora-like glow. As on Earth, this is due to particle radiation hitting the atmosphere, though in this case the charged particles come from Jupiter's magnetic field rather than the solar wind. Aurorae usually occur near the magnetic poles of planets, but Io's are brightest near its equator. Io lacks an intrinsic magnetic field of its own; therefore, electrons traveling along Jupiter's magnetic field near Io directly impact Io's atmosphere. More electrons collide with its atmosphere, producing the brightest aurora, where the field lines are tangent to Io (i.e. near the equator), because the column of gas they pass through is longest there. Aurorae associated with these tangent points on Io are observed to rock with the changing orientation of Jupiter's tilted magnetic dipole. Fainter aurora from oxygen atoms along the limb of Io (the red glows in the image at right), and sodium atoms on Io's night-side (the green glows in the same image) have also been observed.


title: Lombardy

text: Lombardy (, Lombard: "Lombardia" or "Lumbardia"" ") is an administrative region of Italy that covers ; it is located in the northern-central part of the country and has a population of about 10 million people, constituting more than one-sixth of Italy's population. Over a fifth of the Italian gross domestic product (GDP) is produced in the region.


title: Lombardy

text: The Lombardy region is located between the Alps mountain range and tributaries of the Po river, and includes Milan, the largest metropolitan area in the country, and among the largest in the European Union (EU). Of the fifty-eight UNESCO World Heritage Sites in Italy, eleven are in Lombardy. Virgil, Pliny the Elder, Ambrose, Gerolamo Cardano, Caravaggio, Claudio Monteverdi, Antonio Stradivari, Cesare Beccaria, Alessandro Volta and Alessandro Manzoni; and popes John XXIII and Paul VI originated in the area of modern-day Lombardy region.


title: Lombardy

text: The name "Lombardy" comes from "Lombard", which is derived from Late Latin ' ("a Lombard"), which derived from the Proto-Germanic elements + ; equivalent to "long beard". According to some scholars, the second element derives from Proto-Germanic "*bardǭ", "*barduz" ("axe"), related to German ' ("axe"), or the whole word comes from the Proto-Albanian *"Lum bardhi" "white river" (Compare modern Albanian "lum i bardhë").


title: Lombardy

text: The name of the region derives from the name of the people of the Lombards who arrived in Italy in 568 and made Pavia their capital. During the Early Middle Ages, "Lombardy" referred to the Kingdom of the Lombards (), which was ruled by the Germanic Lombard raiders who had controlled most of early Christian Italy since their invasion of Byzantine Italy in CE 568 until the fall of Pavia on the Ticino river, in CE 774 by the Frankish Charlemagne on Pope's behalf. As such, "Lombardy" and "Italy" were almost interchangeable; by the mid-8th century, the Lombards ruled everywhere except the Papal possessions around Rome—roughly modern Lazio and northern Umbria—Venice and some Byzantine possessions in the south—southern Apulia and Calabria; some coastal settlements including Amalfi, Gaeta, Naples and Sorrento; Sicily and Sardinia; their culture is foundational to Italy in the Middle Ages. The term was also used until around 965 in the form ("") as the name for the territory roughly covering modern Apulia, which the Byzantines had recovered from the Lombard rump state Duchy of Benevento.


title: Lombardy

text: Lombardy has a surface area of , and is the fourth-largest region of Italy. It is bordered by Canton Ticino and Canton Graubünden of Switzerland to the north, and by the Italian regions of Trentino-Alto Adige/Südtirol and Veneto to the east, Emilia-Romagna to the south and Piedmont to the west. Lombardy has three natural zones; mountains, hills and plains—the last being divided into "Alta" (high plains) and "Bassa" (low plains).


title: Lombardy

text: The orography of Lombardy is characterised by three distinct belts; a northern mountainous belt constituted by the Alpine relief, a central piedmont area of mostly alluvial pebbly soils, and the Lombard section of the Padan Plain in the south of the region.


title: Lombardy

text: The most important mountainous area is the Alpine zone, which includes the Lepontine and Rhaetian Alps—Piz Bernina (), the Bergamo Alps, the Ortler Alps and the Adamello massif. It is followed by the Alpine foothills zone Prealpi, the main peaks of which are the Grigna Group (), Resegone , and Presolana ().


title: Lombardy

text: The plains of Lombardy, which are formed by alluvial deposits, can be divided into the "Alta"—an upper, permeable ground zone in the north—and the "Bassa", a lower zone dotted by the line of "fontanili", spring waters rising from impermeable ground. Inconsistent with the three distinctions above is the small sub-region of Oltrepò Pavese, which is formed by the Apennine foothills beyond the Po River.


title: Lombardy

text: The Po river marks the southern border of the region for about ; its major tributaries are the Ticino River, which rises in the Bedretto valley in Switzerland and joins the Po near Pavia, the Olona, the Lambro, the Adda, the Oglio and the Mincio.


title: Lombardy

text: The numerous lakes of Lombardy are all of glacial origin and are located in the northern highlands. From west to east, these are: Lake Maggiore, Lake Lugano (both shared with Switzerland), Lake Como, Lake Iseo, Lake Idro, and Lake Garda (the largest lake in Italy). South of the Alps are a succession of low hills of morainic origin that were formed during the Last Glacial Period and small, barely fertile plateaux with typical heaths and conifer woods. A minor mountainous area the Oltrepò Pavese lies in the Apennines range south of the Po.


title: Lombardy

text: The plains have been intensively cultivated for centuries, and little of the original environment remains. The most common trees are elm, alder, sycamore, poplar, willow and hornbeam. In the area of the foothills lakes, however, olive, cypresses and larches grow, as do varieties of subtropical flora such as magnolia, azalea and acacias. Numerous species of endemic flora in the Prealpine area include some species of saxifrage, Lombardy garlic, groundsel and bellflowers.


title: Lombardy

text: The highlands are characterised by the typical vegetation of the Italian Alps. At and below about , oaks or broadleaf trees grow; on the mountain slopes between , beech trees grow at the lowest limits with conifer woods higher up. Shrubs such as rhododendron, dwarf pine and juniper are native to the summit zone beyond .


title: Lombardy

text: Lombardy includes many protected areas. The most important are Stelvio National Park—the largest Italian natural park, with typically alpine wildlife such as red deer, roe deer, ibex, chamois, foxes, ermine and golden eagles; and the Ticino Valley Natural Park, which was instituted in 1974 on the Lombard side of the Ticino River to protect one of the last major examples of fluvial forest in northern Italy. There have also been efforts to protect the endangered Italian agile frog.


title: Lombardy

text: Other parks in the region are the Campo dei Fiori and the Cinque Vette Park, both of which are located in the Province of Varese.


title: Lombardy

text: Lombardy has a wide array of climates due to variance in elevation, proximity to inland water basins, and large metropolitan areas. The climate is mainly humid subtropical (Köppen Cfa), especially in the plains, though with significant variations to the Köppen model, especially in the normally long, damp, and cold winters. There is high seasonal temperature variation; in Milan, average temperature is in January and in July. The plains are often subject to fog during the coldest months.


title: Lombardy

text: In the Alpine foothills with oceanic climate (Köppen Cfb), numerous lakes have a mitigating influence, allowing typically Mediterranean crops (olive, citrus fruit) to grow. In the hills and mountains, the climate is humid continental (Köppen Dfb). In the valleys, it is relatively mild while it can be severely cold with copious snowfalls above .


title: Lombardy

text: Precipitation is more intense in the Prealpine zone, up to annually, but is also abundant n the plains and alpine zones, with an average of annually. Average annual rainfall is .


title: Lombardy

text: It is thought from archaeological findings of ceramics, arrows, axes, and carved stones, the area of current-day Lombardy has been settled at least since the second millennium BC. Well-preserved rock drawings left by ancient Camuni in the Valcamonica depicting animals, people, and symbols were made over 8,000 years before the Iron Age, based on about 300,000 records.


title: Lombardy

text: The many artifacts found in a necropolis near Lake Maggiore and the River Ticino demonstrate the presence of the Golasecca Bronze Age culture that prospered in the western Lombardy between the ninth and the fourth centuries BC. In the following centuries, Lombardy was inhabited by different peoples; the Etruscans founded the city of Mantua and spread the use of writing. It was seat of the Celtic Canegrate culture starting from the 13th century BC, and later of the Celtic Golasecca culture. From the fifth century BC, the area was invaded by more Celtic Gallic tribes coming from north of the Alps. These people settled in several cities including Milan and extended their rule to the Adriatic Sea. Celtic development was halted by the Roman expansion in the Po Valley from the third century BC. After centuries of struggle, in 194 BC, the entirety of modern-day Lombardy became a Roman province called Gallia Cisalpina—"Gaul on the inner side (with respect to Rome) of the Alps".


title: Lombardy

text: The Roman culture and language overwhelmed the former civilisation in the following years, and Lombardy became one of the most-developed and richest areas of Italy with the construction of roads, and the development of agriculture and trade. Important figures were born here, such as Pliny the Elder (in Como) and Virgil (in Mantua). In late antiquity the strategic role of Lombardy was emphasised by the temporary move of the capital of the Western Empire to Mediolanum (Milan). Here, in 313 AD, Roman Emperor Constantine issued the famous "Edict of Milan" that gave freedom of confession to all religions within the Roman Empire.


title: Lombardy

text: During and after the fall of the Western Empire, Lombardy heavily suffered from destruction brought about by a series of invasions by tribal peoples. After 540, Pavia become the permanent capital of the Ostrogothic Kingdom, the fixed site of the court and the royal treasury. The last and most effective invasion was that of the Germanic Lombards or Longobards, whose nation migrated to the region from the Carpathian basin in fear of the conquering Pannonian Avars in 568. The Lombards' long-lasting reign, with its capital in Pavia, gave the current name to the region. There was a close relationship between the Frankish, Bavarian and Lombard nobility for many centuries.


title: Lombardy

text: After the initial struggles, relationships between the Lombard people and the Gallo-Roman peoples improved. The Lombard language and culture was integrated with the Latin culture, leaving evidence in many names, the legal code and laws. The Lombards became intermixed with the Roman population owing to their relatively smaller number. The end of Lombard rule came in 774, when the Frankish king Charlemagne conquered Pavia, deposed Desiderius the last Lombard king, and annexed the Kingdom of Italy—mostly northern and central present-day Italy—to his newly established Holy Roman Empire. Charlemagne was crowned by the Pope on 25 December 800. The former Lombard dukes and nobles were replaced by other German vassals, prince-bishops and marquises. The entire northern part of the Italian peninsula continued to be called "Lombardy" and its population "Lombards" throughout the following centuries.


title: Lombardy

text: In the tenth century, Lombardy, although formally under the rule of the Holy Roman Empire, was included in the kingdom of Italy, of which Pavia remained the capital until 1024. Starting gradually in the late-11th century, Lombardy became divided into many small, autonomous city-states, the medieval communes. Also in the 11th century, the region's economy underwent a significant boom due to improved trading, sartorial manufacturing of silk and wool, and agricultural conditions; arms manufacturing for the purpose of defensive army development, by the German imperial divisions of "Guelphs" ("Welfen") defending Pope and "Ghibellins" ("Wibellingen") defending Emperor, became a significant factor. As in other areas of Italy, this led to a growing self-acknowledgement of the cities, whose increasing wealth made them able to defy the traditional feudal supreme power that was represented by the German emperors and their local legates. This process peaked in the 12th and 13th centuries, when Lombard Leagues formed by allied cities of Lombardy, usually led by Milan, defeated the Hohenstaufen Emperor Frederick I, at Legnano but not his grandson Frederick II at Battle of Cortenuova. Subsequently, among the local city-states, a process of consolidation took place, and by the end of the 14th century, two "signoria" emerged as rival hegemons in Lombardy; Milan and Mantua.


title: Lombardy

text: In the 15th century, the Duchy of Milan was a major political, economical and military force in Europe. Milan and Mantua became centres of the Renaissance, whose culture with people such as Leonardo da Vinci and Andrea Mantegna, and works of art such as da Vinci's "The Last Supper" were highly regarded. The enterprising class of the communes extended its trade and banking activities well into northern Europe; the metanym "Lombard" designated a merchant or banker from northern Italy, for example Lombard Street, London. The name "Lombardy" came to denote the whole of northern Italy until the 15th century and sometimes later. From the 14th century onward, the instability created by the internal and external struggles ended in the creation of noble "seigniories", the most-significant of whom were the Viscontis (later Sforzas) in Milan and of the Gonzagas in Mantua. This wealth, however, attracted the now-more-organised armies of national powers such as France and Austria, which waged a lengthy battle for Lombardy in the late-15th to early 16th centuries.


title: Lombardy

text: After the Battle of Pavia, the Duchy of Milan became a possession of the Habsburgs of Spain; the new rulers did little to improve the economy of Lombardy, instead imposing a growing series of taxes to support their lengthy series of European wars. The eastern part of modern-day Lombardy, including the cities Bergamo and Brescia, was controlled by the Republic of Venice, which had begun to extend its influence in the area from the 14th century onwards. Between the mid-15th century and the battle of Marignano in 1515, the northern part of east Lombardy from Airolo to Chiasso (modern Ticino), and the Valtellina valley came under possession of the Old Swiss Confederacy.


title: Lombardy

text: Pestilences like that of 1628–1630, which Alessandro Manzoni described in his "I Promessi Sposi", and the general decline of Italy's economy in the 17th and 18th centuries halted further development of Lombardy. In 1706 the Austrian Empire came to power, and introduced some economic and social measures that allowed a degree of recovery to occur.


title: Lombardy

text: Austrian rule was interrupted in the late-18th century by the French; under Napoleon, Lombardy became the centre of the Cisalpine Republic and of the Kingdom of Italy, both of which were puppet states of France's First Empire, with Milan as capital and Napoleon as head of state. During this period, Lombardy regained Valtellina from Switzerland.


title: Lombardy

text: The restoration of Austrian rule in 1815 as the Kingdom of Lombardy–Venetia was characterised by a struggle with the new ideals introduced by the Napoleonic era. The popular but short-lived republic established by the 1848 revolution was suppressed, leading to renewed Austrian rule, which ended when Lombardy was annexed to the Kingdom of Italy in 1859 as a result of the Second Italian War of Independence. After the annexation, Lombardy achieved its present-day territorial shape by adding the Oltrepò Pavese, formerly the southern part of the Province of Novara, to the Province of Pavia.


title: Lombardy

text: In early 2020, Lombardy was severely affected by the COVID-19 pandemic, in which Italy was one of the worst-affected countries in Europe. Several towns were quarantined from 22 February after community transmission was documented in Lombardy and Veneto the previous day. The entirety of Lombardy was placed under lockdown on 8 March, followed by all of Italy the following day, making Italy the first country to implement a nationwide lockdown in response to the epidemic, which the World Health Organization (WHO) declared a pandemic on 11 March. The lockdown was extended twice, and the region toughened restrictions on 22 March, banning outdoor exercise and the use of vending machines, but from the beginning of May, following a reported decrease in the number of active cases, restrictions were gradually relaxed.


title: Lombardy

text: , the gross regional product (GRP) of Lombardy was equal to over €366 billion and accounted for about 22% of Italy's total GDP. Lombardy's 2021 GRP was €36,500 per person, more than 25% higher than the national average of €25,729.


title: Lombardy

text: Lombardy's services sector has grown since the 1980s, led by innovative activities in business services, credit and financial services. Lombardy also remains the main industrial area of Italy.


title: Lombardy

text: Lombardy has cultural and economic relationships with many foreign countries including Azerbaijan, Austria, France, Hungary, Switzerland (especially the cantons of Ticino and Graubünden), Canada (the Province of Quebec), Germany (the States of Bavaria, Saxony, and Saxony-Anhalt), Kuwait, the Netherlands (Province of Zuid-Holland), and Russia.


title: Lombardy

text: Lombardy is a member of the Four Motors for Europe, an international economical organization whose other members are Baden-Württemberg in Germany, Catalonia in Spain, and Auvergne-Rhône-Alpes in France. The Lombardy region is also part of the EUSALP, which promotes innovation, sustainability, and economy in the Alpine regions of Austria, France, Liechtenstein, Northern Italy, Southern Germany, Switzerland, and Slovenia, and ARGE ALP, an economic forum of alpine regions of Austria, Northern Italy, Southern Germany, and Switzerland. Economical and cultural relationship are also strong with neighbouring Italian regions Friuli-Venezia Giulia, South Tyrol, Trentino, and Veneto.


title: Lombardy

text: The European Union has developed the Central Europe program in 2014–2020 to foster cooperation between Lombardy and other northern Italian regions and several countries in central Europe.


title: Lombardy

text: The region can be broadly divided into three economic areas: Milan, where the services sector comprises 65.3% of employment; the provinces of Varese, Como, Lecco, Monza and Brianza, Bergamo and Brescia, where there is a highly industrialised economy and a rich agricultural sector; and the provinces of Sondrio, Pavia, Cremona, Mantova and Lodi, where there is consistent agricultural activity and an above-average development of the services sector.


title: Lombardy

text: The productivity of agriculture is enhanced by a use of fertilisers and the traditional abundance of water, which has been boosted since the Middle Ages by the construction of irrigation systems that were partly designed by Leonardo da Vinci. Lower plains are used for fodder crops, cereals (rice, wheat and maize) and sugar beet. Lombardy is one of the main European regions for rice production and together with Piedmont, produces 93% of Italian rice. Cultivation is concentrated in the provinces of Pavia (, Milan (), Lodi and Mantua (). Produce of the higher plains includes cereals, vegetables, fruit trees and mulberries. Fruits and wine are produced in upland areas such as the Prealps and Alps sectors in the north.


title: Lombardy

text: Lombardy is a centre of animal breading, which includes dairy cows (36%) and pigs (50%). The region's dairy industry produces 30% of Italian milk, which is used to produce different types of cheese, totalling about 4,715,130 tonnes, 36% of Italian cheese production.


title: Lombardy

text: There are a lot of variety of sausages produces in Lombardy, like Salame Milano, Salame bergamasco, Salame mantovano, Salame di Varzi, Bastardei, Salam casalin, Salame Brianza, Salame pancettato.


title: Lombardy

text: Vineyards cover . The most important produce is the sparkling wines Franciacorta and Oltrepò Pavese, which are produced using the same traditional method as Champagne, unlike other Italian sparkling wines, which use the charmat method. Lombardy ranks 9 of 20 in production of DOC and DOCG wines with 877.351 hl. Lombardy also produces still red, white and rosé wines made from a variety of grapes, including Nebbiolo wines in the Valtellina region and Trebbiano di Lugana white wines produced with the "Chiaretto"-style rosé along the shores of Lake Garda. The wine region currently has 15 "Denominazione di origine controllata" (DOC), 3 "Denominazione di Origine Controllata e Garantita" (DOCG) and 13 "Indicazione Geografica Tipica" (IGT) designations.The region annually produces around of wine.


title: Lombardy

text: Brescia is also the main production centre of Italian caviar. The world's largest sturgeon farm is located in Calvisano, about south of the city centre, producing 25 tonnes of caviar annually, which is exported worldwide.


title: Lombardy

text: The main activity in Canneto sull'Oglio is the nursery production of broad-leaved plants, for which much land is dedicated. Together with the neighbouring municipalities, the Cannetese Nursery District has been created approximately , which produces an annual turnover of around 150 million euros.


title: Lombardy

text: Italy is a major exporter of heavy helicopters (over ) with market share of about 30%. The headquarters of Leonardo Helicopters Division (ex-AgustaWestland) is in Lombardy, and is responsible for about 33.3% of the company's orders. The region also has a plant of Leonardo Aircraft Division (ex-Aermacchi). The main helicopter design, production and training facilities are located in Cascina Costa di Samarate, Vergiate and Sesto Calende. The company's aircraft division manufactures military training aircraft in Venegono Superiore.


title: Lombardy

text: The world oldest firearms manufacturer Beretta is located in Gardone Val Trompia. Other firearms manufacturers in the region are Tanfoglio and Pedersoli. Ammunition is produced by Fiocchi. The former OTO Melara, now part of Leonardo Electronics Division in Brescia, produces small-calibre naval and airborne weapons.


title: Lombardy

text: There is no longer any car production in Lombardy; the factories of mass-market manufacturers Alfa Romeo, Autobianchi and Innocenti having been closed, abandoned or demolished. Iveco continues to manufacture light trucks Daily in Suzzara and makes lorries EuroCargo in Brescia. Same-Deutz Fahr manufactures tractors under the brands SAME and Lamborghini in Treviglio, and BCS Group makes tractors in Abbiategrasso.


title: Lombardy

text: The best-known automotive-parts suppliers are Brembo, Bergamo (ceramic brake systems); Pirelli, Milan (tyres); and Magneti Marelli, Corbetta (electronic systems, powertrain).


title: Lombardy

text: The largest European semiconductor company STMicroelectronics employs 5,600 people at its plant in a suburb of Milan. Manufacturers of general-purpose integrated circuits (ICs) Agrate Brianza, which employs 4,500, and Cornaredo, which employs 1,100, have R&D and production facilities.


title: Lombardy

text: SAES Getters in Lainate produce getters, alkaline metal dispensers, cathodes and materials for thermal management. Their products are used in various devices such as X-ray tubes, microwave tubes, solid state lasers, electron sources, photomultipliers, radio-frequency amplification systems, night-vision devices, pressure sensors, gyroscopes for navigation systems and MEMS devices.


title: Lombardy

text: Magneti Marelli has headquarters and manufactures automotive electronics in Corbetta. Leonardo Electronics Division in Nerviano designs and develops airborne radar and computers, space equipment. Candy Hoover and Whirlpool (brands: Whirlpool, Indesit, Ariston, Hot Point, Ignis) make home appliances in Lombardy.


title: Lombardy

text: Lombardy has always been an important centre for silk and textile production, notably the cities Pavia, Vigevano and Cremona. Milan is one of the fashion capitals of the world; the city has approximately 12,000 companies, 800 showrooms and 6,000 sales outlets; the city hosts the headquarters of global fashion houses. The best-known high-class shopping district is Quadrilatero della moda.


title: Lombardy

text: In 2009, Milan was regarded as the world fashion capital, surpassing New York, Paris and London. Most of the major Italian fashion brands, such as Luxottica, Valentino, Versace, Prada, Armani and Dolce & Gabbana and Zegna are currently headquartered in Milan.


title: Lombardy

text: Castel Goffredo, in the Province of Mantua, is known locally as the "city of the stocking"; it is an important district for the production of women's hosiery. Fourteen other communities also belonging to this district are:


title: Lombardy

text: Buttons are manufactured in the industrial district of Grumello del Monte (Mabo Group) and lingerie s made in the industrial district of Val Camonica.


title: Lombardy

text: Furniture is manufactured in the industrial district around Brianza, which has an annual turnover of about €2 billion from 1,700 companies. The furniture factories, which have about 40,000 employees, are mainly concentrated in Lissone, Meda, Cantù and Mariano Comense. Other important production centres are Giussano, Seveso, and Seregno. This district has close relations with Milan's design industry. A number of large furniture exhibitions take place in Milan, including "Salone del Mobile Milano".


title: Lombardy

text: The unemployment rate of Lombardy stood at 5% in 2020. In that year, regional unemployment was one of the lowest in Italy.


title: Lombardy

text: Lombardy is one of the most-air-polluted areas of Europe. Because of high levels of industrialisation and the lack of wind due to the region being enclosed between mountain ranges, air pollution remains a severe problem in Lombardy and northern Italy.


title: Lombardy

text: In March 2019, the European Space Agency (ESA) published images taken from its satellites that show a large stain composed of nitrogen dioxide and fine particles above the Po Valley area. Lombardy is the geographic and economic centre of this area, with more than 10 million residents and the highest GRP per inhabitant of the country. Most of its major cities are located in the Po River basin, which crosses the region. The stain analysed by ESA is the main reason Po Valley air pollution levels are so high. Milan also has high levels of ozone and nitrogen oxides, which are mainly produced by cars diesel and petrol engines.


title: Lombardy

text: According to Chicago Energy Policy Institute, which has recently developed the Air Quality Life Index (AQLI), Po Valley air pollution reduces life expectancy by about six months. Air pollution in the Po Valley is connected to livestock and factories. The use of NPK fertilizers, made of nitrogen, phosphorus and potassium, along with manure emissions from intensive breeding and high levels of nitrogen dioxide released by diesel and petrol engines are all causes of pollution in the north of Italy. Lombardy also produces vast amounts of animal waste, a big contributor to pollution. Lombardy produces more than 40% of Italy's milk and over half of the Italian pig production is located in the Po Valley.


title: Lombardy

text: According to research published in The Lancet Planetary Health, in January 2021, Brescia and Bergamo had the highest death rate from fine particulate matter (PM) in Europe.


title: Lombardy

text: The data show many cities in Lombardy and the Po Valley suffer the most-serious impact of poor air quality in Europe, primarily the metropolitan area of Milan, which is 13th in terms of fine particulate impact, with an annual premature death rate of 3,967 – approximately 9% of the total.


title: Lombardy

text: One-sixth of the Italian population, about 10 million people, live in Lombardy (16.2% of the national population; 2% of the European Union population).


title: Lombardy

text: The population is highly concentrated in the Milan metropolitan area (2,029 inh./km) and the Alpine foothills that compose the southern section of the provinces Varese, Como, Lecco, Monza and Brianza and Bergamo, (1,200 inh./km). A lower average population density (250 inh./km) is found in the Po Valley and the lower Brescia valleys; much lower densities (fewer than 60 inh./km) inhabit the northern mountain areas and the southern Oltrepò Pavese subregion.


title: Lombardy

text: The growth of the regional population was particularly sustained during the 1950s–1960s, due to a prolonged economic boom, high birth rates and strong migration inflows—especially from southern Italy. Since the 1980s, Lombardy has become the destination of a large number of international migrants; in the early 21st century, more than a quarter of all foreign-born residents in Italy live in this region. , the Italian National Institute of Statistics (ISTAT) estimated 1,139,430 foreign-born people live in Lombardy, equal to 11.4% of the total population. The primary religion is Roman Catholicism; significant religious minorities include Christian Waldenses, Protestants and Orthodox Christians, as well as Jews, Sikhs and Muslims.


title: Lombardy

text: Lombardy has a system of representative democracy in which the President of the Region (') is the head of government and of a pluriform multi-party system. Executive power is vested in the regional government (') and legislative power is vested in the Regional Council ("").


title: Lombardy

text: From 1945 to the early 1990s, the moderate Christian Democrats maintained a large majority of the popular support and the control of the most important cities and provinces from the end of the Second World War. The opposition Italian Communist Party was a considerable presence only in southern Lombardy and in the working-class districts of Milan; their base, however, was increasingly eroded by the rival centrist Italian Socialist Party until the "Mani Pulite" corruption scandal, which spread from Milan to the whole of Italy, almost completely erased the old political class.


title: Lombardy

text: This, together with general disaffection for the central government, led to the sudden growth of the secessionist Northern League, which was particularly strong in the mountain and rural areas. Since 2002, Lombardy remained strongly conservative, overwhelmingly voting for Silvio Berlusconi in six general elections. The regional capital Milan elected progressive Giuliano Pisapia at the 2011 municipal elections and the 2013 regional elections saw a narrow victory for the centre-right coalition.


title: Lombardy

text: On 22 October 2017 a non-binding autonomy referendum took place in Lombardy. The turnout was 38.3%, of which 95.3% voted in favour. In 2018, the Lombardy regional government was still under negotiation with Rome for the devolution of some powers.


title: Lombardy

text: The region of Lombardy is divided in 11 administrative provinces, 1 metropolitan city and 1,530 communes.


title: Lombardy

text: Lombardy has a rich, diverse cultural heritage ranging from prehistory to the present day. Artifacts from the Roman period and the Renaissance can be found in museums and churches. Major tourist destinations in the region include (in order of arrivals ):


title: Lombardy

text: There are nine UNESCO World Heritage sites wholly or partially located in Lombardy. Some of these comprise several individual objects in different locations. One of the entries has been listed as natural heritage and the others are cultural heritage sites.


title: Lombardy

text: At Monte San Giorgio on the border with Swiss canton Ticino just south of Lake Lugano, a wide range of marine Triassic fossils have been found. During the Triassic period, 240 million years ago, the area was a shallow tropical lagoon. Fossils include reptiles, fish, crustaceans and insects.


title: Lombardy

text: The Rock Drawings in Valcamonica date to between 8000BC and 1000BC, covering prehistoric periods from the Epipaleolithic and Mesolithic to the Iron Age. The engravings depict agricultural and war scenes, alongside more abstract symbols.


title: Lombardy

text: The multi-centred heritage site Prehistoric pile dwellings around the Alps includes 111 objects in France, Switzerland, Italy, Germany, Austria and Slovenia, of which 10 are located in Lombardy. Each of these objects consists of remnants of buildings erected on wooden piles in sub-alpine rivers, lakes and wetlands, which were built between 5000BC and 500BC. In general, only the submerged wooden parts have been preserved in the alluvial sediment, although in some places pile buildings have been reconstructed.


title: Lombardy

text: Another multi-centred site, Longobards in Italy, Places of Power (568–774 A.D.) consists of seven locations across mainland Italy which illustrate the history of the Lombard period. Two of the sites are in modern-day Lombardy: the fortifications (the "castrum" and the Torba Tower), and the church of Santa Maria "foris portas" ("outside the gates") has Byzantinesque frescoes at Castelseprio, and the monastic complex of San Salvatore-Santa Giulia at Brescia. The UNESCO site at Brescia also includes the remains of its Roman forum, the best-preserved in northern Italy.


title: Lombardy

text: The Church and Dominican Convent of Santa Maria delle Grazie in Milan with "The Last Supper" by Leonardo da Vinci represent architectural and painting styles of the 15th-century Renaissance period. The towns Mantua and Sabbioneta are also listed as a combined World Heritage site relating to this period, here focussing more on town-planning aspects of the time than on architectural detail. While Mantua was rebuilt in the 15th and 16th centuries, according to Renaissance principles, Sabbioneta was planned as a new town in the 16th century.


title: Lombardy

text: The Sacri Monti of Piedmont and Lombardy are a group of nine sites in north-west Italy, two of which are in Lombardy. The concept of holy mountains can be found elsewhere in Europe. These sites were created as centres of pilgrimage by placing chapels in the natural landscape, and were loosely modelled on the topography of Jerusalem. In Lombardy, Sacro Monte del Rosario di Varese and Sacro Monte della Beata Vergine del Soccorso, which were built in the early-to mid-17th century, mark the architectural transition from the late Renaissance to the Baroque style.


title: Lombardy

text: Crespi d'Adda is a company town that was founded in 1878 to accommodate workers of a local textile mill. At its height, the town was home to 3,200 employees and their families.


title: Lombardy

text: Parco Naturalistico-Archeologico della Rocca di Manerba del Garda is a fortress of Manerba del Garda.


title: Lombardy

text: The Rhaetian Railway in the Albula/Bernina Landscapes is mostly located in the Swiss canton Graubünden, but extends over the border into Tirano. The site is listed because of the complex railway engineering (tunnels, viaducts and avalanche galleries) necessary to take the narrow-gauge railway across the main chain of the Alps. The two railway lines were opened in several stages between 1904 and 1910.


title: Lombardy

text: The is a transnational system of fortifications that were built by the Republic of Venice on its mainland domains ("Stato da Terra") and its territories stretching along the Adriatic coast ("Stato da Mar"). This site includes the fortified city Bergamo.


title: Lombardy

text: Lombardy has more than 300 museums in subjects such as ethnographic, historical, technical-scientific, artistic and naturalistic fields. Among the region's most-famous museums are:


title: Lombardy

text: Rice is popular in Lombardy; the region is the largest in Europe for rice production and in particular the province of Pavia, where over are cultivated. Rice is often used in soups and "risotti", such as "risotto alla milanese", with saffron. In Monza, a popular recipe adds pieces of sausages to the risotto, while in Pavia they eat Carthusian risotto, according to the legend created by the monks of the Certosa, which is based on crayfish, carrots and onions. They also eat risotto with eye beans, and a version with sausage and bonarda, and risotto with common hops (ürtis in pavese dialect). Polenta is common throughout the region.


title: Lombardy

text: Regional cheeses include "Robiola", "Crescenza", "Taleggio", "Gorgonzola" and "Grana Padano". Butter and cream are used. Single pot dishes, which take little work to prepare, are popular. Common types of pasta include Casoncelli in Brescia and Bergamo and Pizzoccheri in Valtellina. In Mantua, festivals feature "tortelli di zucca" (ravioli with pumpkin filling) accompanied by melted butter and followed by turkey stuffed with chicken or other stewed meats. Among typical regional desserts is Nocciolini di Canzo—dry biscuits.


title: Lombardy

text: Each of Lombardy's 12 provinces has its own musical traditions. Bergamo is famous for being the birthplace of Gaetano Donizetti and home of the Teatro Donizetti; Brescia hosts the impressive 1709 Teatro Grande; Cremona is regarded as the origin of the violin and is home to several of the most prestigious luthiers; and Mantua was one of the founding and most important cities in 16th- and 17th-century opera and classical music.


title: Lombardy

text: Other cities such as Lecco, Lodi, Varese and Pavia (Teatro Fraschini) also have rich musical traditions, but Milan is the centre of the Lombard musical scene. It was the workplace of Giuseppe Verdi, one of the most famous and influential 19th-century opera composers. The province has acclaimed theatres, such as the Piccolo Teatro and the Teatro Arcimboldi; however, the most famous is the 1778 Teatro alla Scala (popularly La Scala), one of the most important and prestigious opera houses in the world.


title: Lombardy

text: Lombard is widely used in Lombardy, in diglossia with Italian. Lombard is a language belonging to the Gallo-Italic group within the Romance languages. It is a cluster of homogeneous varieties used by at least 3,500,000 native speakers in Lombardy and some areas of neighbouring regions, such as the eastern part of Piedmont and the southern Switzerland cantons of Ticino and Graubünden.


title: Lombardy

text: The Lombard language should not be confused with that of the Lombards – Lombardic language, a Germanic language extinct since the Middle Ages.


title: Lombardy

text: The most popular sport in Lombardy is football. Lombardy has some of the most-successful men's football teams in the country. In the 2022-2023 Serie A season, Lombardy hosts 4 out of 20 teams: A.C. Milan and Inter Milan (both based in Milan) and Atalanta B.C. (based in Bergamo); A.C. Monza (based in Monza). Other big teams of the region are Brescia Calcio, and U.S. Cremonese playing in the 2020-21 Serie B, and Calcio Lecco 1912, U.C. AlbinoLeffe, Como 1907, Aurora Pro Patria 1919, A.C. Renate, A.S. Giana Erminio, S.S.D. Pro Sesto and U.S. Pergolettese 1932 playing in the 2020-21 Serie C.


title: Lombardy

text: Olimpia Milano (based in Milan) is the most-successful men's basketball team in Italy. In the 2020–21 LBA season 5 teams out of 15 are from Lombardy (Olimpia Milano, Pallacanestro Brescia, Pallacanestro Varese, Pallacanestro Cantù, Guerino Vanoli Basket).


title: Lombardy

text: Milan will host the 2026 Winter Olympics alongside Cortina d'Ampezzo. The Autodromo Nazionale di Monza, located outside Milan, hosts the Formula One Italian Grand Prix. The Giro d'Italia, a famous annual bicycle race, usually ends in Milan. Alpine skiing is also important for the region; the FIS Alpine Ski World Cup holds an annual race in Bormio.


title: Æ

text: Æ (lowercase: æ) is a character formed from the letters "a" and "e", originally a ligature representing the Latin diphthong "ae". It has been promoted to the status of a letter in some languages, including Danish, Norwegian, Icelandic, and Faroese. It was also used in Old Swedish before being changed to ä. Today, the International Phonetic Alphabet uses it to represent the near-open front unrounded vowel (the sound represented by the 'a' in the English word "cat"). Diacritic variants include Ǣ/ǣ, Ǽ/ǽ, Æ̀/æ̀, Æ̂/æ̂ and Æ̃/æ̃.


title: Æ

text: As a letter of the Old English Latin alphabet, it was called , "ash tree", after the Anglo-Saxon futhorc rune ᚫ which it transliterated; its traditional name in English is still ash, or æsh if the ligature is included.


title: Æ

text: In Classical Latin, the combination "AE" denotes the diphthong , which had a value similar to the long "i" in "fine" as pronounced in most dialects of Modern English. Both classical and present practice is to write the letters separately, but the ligature was used in medieval and early modern writings, in part because "æ" was reduced to the simple vowel during the Roman Empire. In some medieval scripts, the ligature was simplified to "ę", an "e" with ogonek, called the "e caudata" (Latin for "tailed e"). That was further simplified into a plain "e", which may have influenced or been influenced by the pronunciation change. However, the ligature is still relatively common in liturgical books and musical scores.


title: Æ

text: In the modern French alphabet, "æ" (called "") is used to spell Latin and Greek borrowings like "curriculum vitæ", "et cætera", "ex æquo", "tænia", and the first name Lætitia. It is mentioned in the name of Serge Gainsbourg's song "Elaeudanla Téïtéïa", a reading of the French spelling of the name Lætitia: "L, A, E dans l'A, T, I, T, I, A."


title: Æ

text: In English, usage of the ligature varies between different places and contexts, but it is fairly rare. In modern typography, if technological limitations make the use of "æ" difficult (such as in use of typewriters, telegraphs, or ASCII), the digraph "ae" is often used instead.


title: Æ

text: In the United States, the issue of the ligature is sidestepped in many cases by use of a simplified spelling with "e", as happened with œ as well. Usage, however, may vary; for example, "medieval" is now more common than "mediaeval" (and the now old-fashioned "mediæval") even in the United Kingdom, but "archaeology" is preferred over "archeology", even in the US.


title: Æ

text: Given their long history, ligatures are sometimes used to show archaism or in literal quotations of historic sources; for instance, in those contexts, words such as "dæmon" and "æther" are often so spelled.


title: Æ

text: The ligature is seen on gravestones of the 19th century, short for "ætate" ("at the age (of)"): "Æ "xx"Ys, "yy"Ms, "zz"Ds." It is also common in formal typography (invitations, resolutions, announcements, and some government documents); for example, the Court Circular has continued to use the spelling "orthopædic" well into the 21st century.


title: Æ

text: In numismatics, "Æ" is used as an abbreviation for "bronze", derived from the Latin "aes" ("aere" in the ablative, "from bronze").


title: Æ

text: In Old English, "æ" represented a sound between "a" and "e" (), very much like the short "a" of "cat" in many dialects of Modern English. If long vowels are distinguished from short vowels, the long version is marked with a macron ("ǣ") or, less commonly, an acute ("ǽ").


title: Æ

text: In Old Norse, "æ" represents the long vowel . The short version of the same vowel, , if it is distinguished from , is written as "ę".


title: Æ

text: One of its etymological origins is Old Norse é (the other is Old Norse æ), which is particularly evident in the dialects of Suðuroy, where Æ is or :


title: Æ

text: In Danish and Norwegian, "æ" is a separate letter of the alphabet that represents a monophthong. It follows "z" and precedes "ø" and "å". In Norwegian, there are four ways of pronouncing the letter:


title: Æ

text: In many northern, western, and southwestern Norwegian dialects and in the western Danish dialects of and Southern Jutland, has a significant meaning: the first person singular pronoun I. It is thus a normal spoken word and is usually written when such dialects are rendered in writing. It is pronounced , contrary to the definite article which is pronounced .


title: Æ

text: In western and southern Jutish dialects of Danish, is also the proclitic definite article: (the house), as opposed to Standard Danish and all other Nordic varieties which have enclitic definite articles (Danish, Swedish, Norwegian: ; Icelandic, Faroese: [the house]).


title: Æ

text: The equivalent letter in German, Swedish, and Finnish is , but it is not located at the same place within the alphabet. In German, it is not a separate letter from "A" but in Swedish, it is the second-to-last letter (between å and ö).


title: Æ

text: In the normalized spelling of Middle High German, represents a long vowel . The actual spelling in the manuscripts varies, however.


title: Æ

text: Ossetic used the letter "æ" when it was written using the Latin script from 1923 to 1938. Since then, Ossetian has used a Cyrillic alphabet with an identical-looking letter (Ӕ and ӕ). It is pronounced as a mid-central vowel (schwa).


title: Æ

text: The letter "æ" is used in the official orthography of Kawésqar spoken in Chile and also in that of the Fuegian language Yaghan.


title: Æ

text: The symbol is also used in the International Phonetic Alphabet (IPA) to denote a near-open front unrounded vowel like in the word "cat" in many dialects of Modern English, which is the sound that was most likely represented by the Old English letter. In the IPA, it is always in lowercase. is a superscript IPA letter


title: Æ

text: The Latin letters are frequently used in place of the Cyrillic Ӕ and ӕ in Cyrillic texts (such as on Ossetian sites on the Internet).


title: Tibet Autonomous Region

text: The Tibet Autonomous Region or Xizang Autonomous Region, often shortened to Tibet or Xizang, is a province-level autonomous region of the People's Republic of China in Southwest China. It was overlayed on the traditional Tibetan regions of Ü-Tsang and Kham.


title: Tibet Autonomous Region

text: It was formally established in 1965 to replace the Tibet Area, the former administrative division of the People's Republic of China (PRC) established after the annexation of Tibet. The establishment was about five years after the 1959 Tibetan uprising and the dismissal of the Kashag, and about 13 years after the original annexation.


title: Tibet Autonomous Region

text: The current borders of the Tibet Autonomous Region were generally established in the 18th century and include about half of historic Tibet, or the ethno-cultural Tibet. The Tibet Autonomous Region spans over and is the second-largest province-level division of China by area, after Xinjiang. Due to its harsh and rugged terrain, it is sparsely populated at just over 3.6 million people with a population density of .


title: Tibet Autonomous Region

text: Yarlung kings founded the Tibetan Empire in 618. By the end of the 8th century, the empire reached its greatest extent. After a civil war, the empire broke up in 842. The royal lineage fragmented and ruled over small kingdoms such as Guge, Maryul and Nyingma. The Mongol Empire conquered Tibet in 1244 but granted the region a degree of political autonomy. Kublai Khan later incorporated Tibetans into his Yuan empire (1271–1368). The Sakya lama Drogön Chögyal Phagpa became religious teacher to Kublai in the 1250s, and was made the head of the Tibetan region administration .


title: Tibet Autonomous Region

text: From 1354 to 1642, Central Tibet (Ü-Tsang) was ruled by a succession of dynasties from Nêdong, Shigatse and Lhasa. In 1642, the Ganden Phodrang court of the 5th Dalai Lama was established by Güshi Khan of the Khoshut Khanate, who was enthroned as King (chogyal) of Tibet. The Khoshuts ruled until 1717, when they were overthrown by the Dzungar Khanate. The Dzungar forces were in turn expelled by the 1720 Manchu expedition to Tibet during the Dzungar–Qing Wars. This began Qing rule over Tibet: Tibet came under the direct control of the central Chinese government.


title: Tibet Autonomous Region

text: Despite some politically-charged historical debate on the exact nature of Sino-Tibetan relations, most historians agree that Tibet under the Ganden Phodrang (1642 to ) was an independent state, albeit the country had been under different foreign suzerainties for much of its history – including during the Ming dynasty period (1368–1644).


title: Tibet Autonomous Region

text: From 1912 to 1950, the State of Tibet became "de facto" independent after the fall of the Qing dynasty, like many other regions of the successor Republic of China. The Republic of China régime, preoccupied with fractious warlordism (1916–1928), civil war (1927–1949) and Japanese invasion (1937–1945), failed to assert its authority in Tibet. Other smaller kingdoms of ethno-cultural Tibet in eastern Kham and Amdo had been under "de jure" administration of the Chinese dynastic government since the mid-18th century; they variously form parts of the provinces of Qinghai, Gansu, Sichuan and Yunnan. (See also: Xikang Province)


title: Tibet Autonomous Region

text: In 1950, after the 1949 establishment of the People's Republic of China, the People's Liberation Army entered Tibet and defeated the Tibetan local army in a battle fought near the city of Chamdo. In 1951, Tibetan representatives signed a 17-point agreement with the Central People's Government affirming China's sovereignty over Tibet and the incorporation of Tibet into China. The 14th Dalai Lama ratified the agreement in October 1951. After a failed violent uprising, the 14th Dalai Lama fled to India in 1959 and renounced the 17-point agreement. The establishment of the Tibet Autonomous Region in 1965 made Tibet a provincial-level division of China.


title: Tibet Autonomous Region

text: The Tibet Autonomous Region is located on the Tibetan Plateau, the highest region on Earth. In northern Tibet elevations reach an average of over . Mount Everest is located on Tibet's border with Nepal.


title: Tibet Autonomous Region

text: China's provincial-level areas of Xinjiang, Qinghai and Sichuan lie to the north, northeast and east, respectively, of the Tibet AR. There is also a short border with Yunnan Province to the southeast. The countries to the south and southwest are Myanmar, India, Bhutan, and Nepal. China claims Arunachal Pradesh administered by India as part of the Tibet Autonomous Region. It also claims some areas adjoining the Chumbi Valley that are recognised as Bhutan's territory, and some areas of eastern Ladakh claimed by India. India and China agreed to respect the Line of Actual Control in a bilateral agreement signed on September 7th, 1993.


title: Tibet Autonomous Region

text: Physically, the Tibet AR may be divided into two parts: the lakes region in the west and north-west and the river region, which spreads out on three sides of the former on the east, south and west. Both regions receive limited amounts of rainfall as they lie in the rain shadow of the Himalayas; however, the region names are useful in contrasting their hydrological structures, and also in contrasting their different cultural uses: nomadic in the lake region and agricultural in the river region. On the south the Tibet AR is bounded by the Himalayas, and on the north by a broad mountain system. The system at no point narrows to a single range; generally there are three or four across its breadth. As a whole the system forms the watershed between rivers flowing to the Indian Ocean — the Indus, Brahmaputra and Salween and its tributaries — and the streams flowing into the undrained salt lakes to the north.


title: Tibet Autonomous Region

text: The lake region extends from the Pangong Tso Lake in Ladakh, Lake Rakshastal, Yamdrok Lake and Lake Manasarovar near the source of the Indus River, to the sources of the Salween, the Mekong and the Yangtze. Other lakes include Dagze Co, Namtso, and Pagsum Co. The lake region is a wind-swept Alpine grassland. This region is called the Chang Tang (Byang sang) or 'Northern Plateau' by the people of Tibet. It is broad and covers an area about equal to that of France. Due to its great distance from the ocean it is extremely arid and possesses no river outlet. The mountain ranges are spread out, rounded, disconnected, and separated by relatively flat valleys.


title: Tibet Autonomous Region

text: The Tibet AR is dotted over with large and small lakes, generally salt or alkaline, and intersected by streams. Due to the presence of discontinuous permafrost over the Chang Tang, the soil is boggy and covered with tussocks of grass, thus resembling the Siberian tundra. Salt and fresh-water lakes are intermingled. The lakes are generally without outlet, or have only a small effluent. The deposits consist of soda, potash, borax and common salt. The lake region is noted for a vast number of hot springs, which are widely distributed between the Himalaya and 34° N, but are most numerous to the west of Tengri Nor (north-west of Lhasa). So intense is the cold in this part of Tibet that these springs are sometimes represented by columns of ice, the nearly boiling water having frozen in the act of ejection.


title: Tibet Autonomous Region

text: The river region is characterized by fertile mountain valleys and includes the Yarlung Tsangpo River (the upper courses of the Brahmaputra) and its major tributary, the Nyang River, the Salween, the Yangtze, the Mekong, and the Yellow River. The Yarlung Tsangpo Canyon, formed by a horseshoe bend in the river where it flows around Namcha Barwa, is the deepest and possibly longest canyon in the world. Among the mountains there are many narrow valleys. The valleys of Lhasa, Xigazê, Gyantse and the Brahmaputra are free from permafrost, covered with good soil and groves of trees, well irrigated, and richly cultivated.


title: Tibet Autonomous Region

text: The South Tibet Valley is formed by the Yarlung Tsangpo River during its middle reaches, where it travels from west to east. The valley is approximately long and wide. The valley descends from above sea level to . The mountains on either side of the valley are usually around high. Lakes here include Lake Paiku and Lake Puma Yumco.


title: Tibet Autonomous Region

text: The Tibet Autonomous Region is a province-level entity of the People's Republic of China. Chinese law nominally guarantees some autonomy in the areas of education and language policy. Like other subdivisions of China, routine administration is carried out by a People's Government, headed by a chairman, who has been an ethnic Tibetan except for an interregnum during the Cultural Revolution. As with other Chinese provinces, the Chairman carries out work under the direction of the regional secretary of the Chinese Communist Party. The regional standing committee of the Communist Party serves as the top rung of political power in the region. The current Chairman is Yan Jinhai and the current party secretary is Wang Junzheng.


title: Tibet Autonomous Region

text: The Autonomous Region is divided into seven prefecture-level divisions: six prefecture-level cities and one prefecture.


title: Tibet Autonomous Region

text: These in turn are subdivided into a total of 66 counties and 8 districts (Chengguan, Doilungdêqên, Dagzê, Samzhubzê, Karub, Bayi, Nêdong, and Seni).


title: Tibet Autonomous Region

text: With an average of only two people per square kilometer, Tibet has the lowest population density among any of the Chinese province-level administrative regions, mostly due to its harsh and rugged terrain.


title: Tibet Autonomous Region

text: The ethnic Tibetans, comprising 90.48% of the population, mainly adhere to Tibetan Buddhism and Bön, although there is an ethnic Tibetan Muslim community. Other Muslim ethnic groups such as the Hui and the Salar have inhabited the region. There is also a tiny Tibetan Christian community in eastern Tibet. Smaller tribal groups such as the Monpa and Lhoba, who follow a combination of Tibetan Buddhism and spirit worship, are found mainly in the southeastern parts of the region.


title: Tibet Autonomous Region

text: Historically, the population of Tibet consisted of primarily ethnic Tibetans. According to tradition the original ancestors of the Tibetan people, as represented by the six red bands in the Tibetan flag, are: the Se, Mu, Dong, Tong, Dru and Ra. Other traditional ethnic groups with significant population or with the majority of the ethnic group reside in Tibet include Bai people, Blang, Bonan, Dongxiang, Han, Hui people, Lhoba, Lisu people, Miao, Mongols, Monguor (Tu people), Menba (Monpa), Mosuo, Nakhi, Qiang, Nu people, Pumi, Salar, and Yi people.


title: Tibet Autonomous Region

text: According to the Encyclopædia Britannica Eleventh Edition published between 1910 and 1911, the total population of the Tibetan capital of Lhasa, including the lamas in the city and vicinity, was about 30,000, and the permanent population also included Chinese families (about 2,000).


title: Tibet Autonomous Region

text: Most Han people in the Tibet Autonomous Region (8.17% of the total population) are recent migrants, because all of the Han were expelled from "Outer Tibet" (Central Tibet) following the British invasion until the establishment of the PRC.


title: Tibet Autonomous Region

text: Only 8% of Han people have household registration in TAR, others keep their household registration in place of origin.


title: Tibet Autonomous Region

text: Tibetan scholars and exiles claim that, with the 2006 completion of the Qingzang Railway connecting the Tibet Autonomous Region to Qinghai Province, there has been an "acceleration" of Han migration into the region. The Tibetan government-in-exile based in northern India asserts that the PRC is promoting the migration of Han workers and soldiers to Tibet to marginalize and assimilate the locals.


title: Tibet Autonomous Region

text: The main religion in Tibet has been Buddhism since its outspread in the 8th century AD. Before the arrival of Buddhism, the main religion among Tibetans was an indigenous shamanic and animistic religion, Bon, which now comprises a sizeable minority and influenced the formation of Tibetan Buddhism.


title: Tibet Autonomous Region

text: According to estimates from the International Religious Freedom Report of 2012, most Tibetans (who comprise 91% of the population of the Tibet Autonomous Region) are adherents of Tibetan Buddhism, while a minority of 400,000 people are followers the native Bon or folk religions which share the image of Confucius (Tibetan: "Kongtse Trulgyi Gyalpo") with Chinese folk religion, though in a different light. According to some reports, the government of China has been promoting the Bon religion, linking it with Confucianism.


title: Tibet Autonomous Region

text: Most of the Han Chinese who reside in Tibet practice their native Chinese folk religion (). There is a Guandi Temple of Lhasa () where the Chinese god of war Guandi is identified with the cross-ethnic Chinese, Tibetan, Mongol and Manchu deity Gesar. The temple is built according to both Chinese and Tibetan architecture. It was first erected in 1792 under the Qing dynasty and renovated around 2013 after decades of disrepair.


title: Tibet Autonomous Region

text: Built or rebuilt between 2014 and 2015 is the Guandi Temple of Qomolangma (Mount Everest), on Ganggar Mount, in Tingri County.


title: Tibet Autonomous Region

text: There are four mosques in the Tibet Autonomous Region with approximately 4,000 to 5,000 Muslim adherents, although a 2010 Chinese survey found a higher proportion of 0.4%. There is a Catholic church with 700 parishioners, which is located in the traditionally Catholic community of Yanjing in the east of the region.


title: Tibet Autonomous Region

text: Before the annexation of Tibet by the People's Republic of China in 1951, Tibet was ruled by a theocracy and had a caste-like social hierarchy. Human rights in Tibet prior to its incorporation into the People's Republic of China differed considerably from those in the modern era. Due to tight control of press in mainland China, including the Tibet Autonomous Region, it is difficult to accurately determine the scope of human rights abuses.


title: Tibet Autonomous Region

text: Critics of the Chinese Communist Party (CCP) say the CCP's official aim to eliminate "the three evils of separatism, terrorism and religious extremism" is used as a pretext for human rights abuses. A 1992 Amnesty International report stated that judicial standards in the Tibet Autonomous Region were not up to "international standards". The report charged the CCP government with keeping political prisoners and prisoners of conscience; ill-treatment of detainees, including torture, and inaction in the face of ill-treatment; the use of the death penalty; extrajudicial executions; and forced abortion and sterilization.


title: Tibet Autonomous Region

text: Beginning in 2006, 280,000 Tibetans who lived in traditional villages and as nomadic herdsmen have been forcefully relocated into villages and towns. In those areas, new housing was built and existing houses were remodelled to serve a total of 2 million people.


title: Tibet Autonomous Region

text: Those living in substandard housing were required to dismantle their houses and remodel them to government standards. Much of the expense was borne by the residents themselves, often through bank loans. The population transfer program, which was first implemented in Qinghai where 300,000 nomads were resettled, is called "Comfortable Housing", which is part of the "Build a New Socialist Countryside" program. Its effect on Tibetan culture has been criticized by exiles and human rights groups. Finding employment is difficult for relocated persons who have only agrarian skills. Income shortfalls are offset by government support programs. It was announced that in 2011 that 20,000 Communist Party cadres will be placed in the new towns.


title: Tibet Autonomous Region

text: From the 1951 Seventeen Point Agreement to 2003, life expectancy in Tibet increased from thirty-six years to sixty-seven years with infant mortality and absolute poverty declining steadily.


title: Tibet Autonomous Region

text: The Tibetans traditionally depended upon agriculture for survival. Since the 1980s, however, other jobs such as taxi-driving and hotel retail work have become available in the wake of Chinese economic reform. In 2011, Tibet's nominal GDP topped 60.5 billion yuan (US$9.60 billion), nearly more than seven times as big as the 11.78 billion yuan (US$1.47 billion) in 2000. Economic growth since the beginning of the 21st century has averaged over 10 percent a year. By 2020 the GDP of the region surpassed 190 billion yuan (US$29.2 billion).


title: Tibet Autonomous Region

text: While traditional agriculture and animal husbandry continue to lead the area's economy, in 2005 the tertiary sector contributed more than half of its GDP growth, the first time it surpassed the area's primary industry. Rich reserves of natural resources and raw materials have yet to lead to the creation of a strong secondary sector, due in large part to the province's inhospitable terrain, low population density, an underdeveloped infrastructure and the high cost of extraction.


title: Tibet Autonomous Region

text: The collection of caterpillar fungus ("Cordyceps sinensis", known in Tibetan as "Yartsa Gunbu") in late spring / early summer is in many areas the most important source of cash for rural households. It contributes an average of 40% to rural cash income and 8.5% to the Tibet Autonomous Region's GDP.


title: Tibet Autonomous Region

text: The re-opening of the Nathu La pass (on southern Tibet's border with India) should facilitate Sino-Indian border trade and boost Tibet's economy.


title: Tibet Autonomous Region

text: In 2008, Chinese news media reported that the per capita disposable incomes of urban and rural residents in Tibet averaged 12,482 yuan (US$1,798) and 3,176 yuan (US$457) respectively.


title: Tibet Autonomous Region

text: The China Western Development policy was adopted in 2000 by the central government to boost economic development in western China, including the Tibet Autonomous Region.


title: Tibet Autonomous Region

text: There are 4 universities and 3 special colleges in Tibet, including Tibet University, Tibet University for Nationalities, Tibet Tibetan Medical University, Tibet Agricultural and Animal Husbandry College, Lhasa Teachers College, Tibet Police College and Tibet Vocational and Technical College.


title: Tibet Autonomous Region

text: Foreign tourists were first permitted to visit the Tibet Autonomous Region in the 1980s. While the main attraction is the Potala Palace in Lhasa, there are many other popular tourist destinations including the Jokhang Temple, Namtso Lake, and Tashilhunpo Monastery. Nonetheless, tourism in Tibet is still restricted for non-Chinese passport holders (including citizens of the Republic of China from Taiwan), and foreigners must apply for a Tibet Entry Permit to enter the region.


title: Tibet Autonomous Region

text: A 2019 white paper from The State Council Information Office of the People's Republic of China reported Tibet’s road system has achieved a total of 118,800 km.


title: Tibet Autonomous Region

text: The civil airports in Tibet are Lhasa Gonggar Airport, Qamdo Bangda Airport, Nyingchi Airport, and the Gunsa Airport.


title: Tibet Autonomous Region

text: Gunsa Airport in Ngari Prefecture began operations on 1 July 2010, to become the fourth civil airport in China's Tibet Autonomous Region.


title: Tibet Autonomous Region

text: Announced in 2010, Nagqu Dagring Airport was expected to become the world's highest altitude airport, at 4,436 meters above sea level. However, in 2015 it was reported that construction of the airport has been delayed due to the necessity to develop higher technological standards.


title: Tibet Autonomous Region

text: The Qinghai–Tibet Railway from Golmud to Lhasa was completed on 12 October 2005. It opened to regular trial service on 1 July 2006. Five pairs of passenger trains run between Golmud and Lhasa, with connections onward to Beijing, Chengdu, Chongqing, Guangzhou, Shanghai, Xining and Lanzhou. The line includes the Tanggula Pass, which, at 5,072 m (16,640 ft) above sea level, is the world's highest railway.


title: Tibet Autonomous Region

text: The Lhasa–Xigazê Railway branch from Lhasa to Xigazê was completed in 2014. It opened to regular service on 15 August 2014. The planned China–Nepal railway will connect Xigazê to Kathmandu, capital of Nepal, and is expected to be completed around 2027.


title: Tibet Autonomous Region

text: The construction of the Sichuan–Tibet Railway began in 2015. The line is expected to be completed around 2025.


title: Lagrange point

text: In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the influence of two massive orbiting bodies. Mathematically, this involves the solution of the restricted three-body problem in which two bodies are far more massive than the third.


title: Lagrange point

text: Normally, the two massive bodies exert an unbalanced gravitational force at a point, altering the orbit of whatever is at that point. At the Lagrange points, the gravitational forces of the two large bodies and the centrifugal force balance each other. This can make Lagrange points an excellent location for satellites, as few orbit corrections are needed to maintain the desired orbit. Small objects placed in orbit at Lagrange points are in equilibrium in at least two directions relative to the center of mass of the large bodies.


title: Lagrange point

text: For any combination of two orbital bodies there are five Lagrange points, L to L, all in the orbital plane of the two large bodies. There are five Lagrange points for the Sun–Earth system, and five "different" Lagrange points for the Earth–Moon system. L, L, and L are on the line through the centers of the two large bodies, while L and L each act as the third vertex of an equilateral triangle formed with the centers of the two large bodies.


title: Lagrange point

text: When the mass ratio of the two bodies is large enough, the L and L points are stable points meaning that objects can orbit them, and that they have a tendency to pull objects into them. Several planets have trojan asteroids near their L and L points with respect to the Sun; Jupiter has more than one million of these trojans. Artificial satellites, for example the James Webb Space Telescope, have been placed at L and L with respect to the Sun and Earth, and with respect to the Earth and the Moon. The Lagrange points have been proposed for uses in space exploration.


title: Lagrange point

text: The three collinear Lagrange points (L, L, L) were discovered by Leonhard Euler around 1750, a decade before Joseph-Louis Lagrange discovered the remaining two.


title: Lagrange point

text: In 1772, Lagrange published an "Essay on the three-body problem". In the first chapter he considered the general three-body problem. From that, in the second chapter, he demonstrated two special constant-pattern solutions, the collinear and the equilateral, for any three masses, with circular orbits.


title: Lagrange point

text: The point lies on the line defined between the two large masses "M" and "M". It is the point where the gravitational attraction of "M" and that of "M" combine to produce an equilibrium. An object that orbits the Sun more closely than Earth would normally have a shorter orbital period than Earth, but that ignores the effect of Earth's own gravitational pull. If the object is directly between Earth and the Sun, then Earth's gravity counteracts some of the Sun's pull on the object, and therefore increases the orbital period of the object. The closer to Earth the object is, the greater this effect is. At the point, the orbital period of the object becomes exactly equal to Earth's orbital period. is about 1.5 million kilometers from Earth, or 0.01 au.


title: Lagrange point

text: The point lies on the line through the two large masses, beyond the smaller of the two. Here, the gravitational forces of the two large masses balance the centrifugal effect on a body at . On the opposite side of Earth from the Sun, the orbital period of an object would normally be greater than that of Earth. The extra pull of Earth's gravity decreases the orbital period of the object, and at the point that orbital period becomes equal to Earth's. Like L, L is about 1.5 million kilometers or 0.01 au from Earth. An example of a spacecraft at L is the James Webb Space Telescope, designed to operate near the Earth–Sun L. Earlier examples include the Wilkinson Microwave Anisotropy Probe and its successor, "Planck".


title: Lagrange point

text: The point lies on the line defined by the two large masses, beyond the larger of the two. Within the Sun–Earth system, the point exists on the opposite side of the Sun, a little outside Earth's orbit and slightly closer to the center of the Sun than Earth is. This placement occurs because the Sun is also affected by Earth's gravity and so orbits around the two bodies' barycenter, which is well inside the body of the Sun. An object at Earth's distance from the Sun would have an orbital period of one year if only the Sun's gravity is considered. But an object on the opposite side of the Sun from Earth and directly in line with both "feels" Earth's gravity adding slightly to the Sun's and therefore must orbit a little farther from the barycenter of Earth and Sun in order to have the same 1-year period. It is at the point that the combined pull of Earth and Sun causes the object to orbit with the same period as Earth, in effect orbiting an Earth+Sun mass with the Earth-Sun barycenter at one focus of its orbit.


title: Lagrange point

text: The and points lie at the third vertices of the two equilateral triangles in the plane of orbit whose common base is the line between the centers of the two masses, such that the point lies 60° ahead of () or behind () the smaller mass with regard to its orbit around the larger mass.


title: Lagrange point

text: The triangular points ( and ) are stable equilibria, provided that the ratio of is greater than 24.96. This is the case for the Sun–Earth system, the Sun–Jupiter system, and, by a smaller margin, the Earth–Moon system. When a body at these points is perturbed, it moves away from the point, but the factor opposite of that which is increased or decreased by the perturbation (either gravity or angular momentum-induced speed) will also increase or decrease, bending the object's path into a stable, kidney bean-shaped orbit around the point (as seen in the corotating frame of reference).


title: Lagrange point

text: The points , , and are positions of unstable equilibrium. Any object orbiting at , , or will tend to fall out of orbit; it is therefore rare to find natural objects there, and spacecraft inhabiting these areas must employ station keeping in order to maintain their position.


title: Lagrange point

text: Due to the natural stability of and , it is common for natural objects to be found orbiting in those Lagrange points of planetary systems. Objects that inhabit those points are generically referred to as 'trojans' or 'trojan asteroids'. The name derives from the names that were given to asteroids discovered orbiting at the Sun–Jupiter and points, which were taken from mythological characters appearing in Homer's "Iliad", an epic poem set during the Trojan War. Asteroids at the point, ahead of Jupiter, are named after Greek characters in the "Iliad" and referred to as the "Greek camp". Those at the point are named after Trojan characters and referred to as the "Trojan camp". Both camps are considered to be types of trojan bodies.


title: Lagrange point

text: As the Sun and Jupiter are the two most massive objects in the Solar System, there are more Sun–Jupiter trojans than for any other pair of bodies. However, smaller numbers of objects are known at the Lagrange points of other orbital systems:


title: Lagrange point

text: Objects which are on horseshoe orbits are sometimes erroneously described as trojans, but do not occupy Lagrange points. Known objects on horseshoe orbits include 3753 Cruithne with Earth, and Saturn's moons Epimetheus and Janus.


title: Lagrange point

text: Lagrange points are the constant-pattern solutions of the restricted three-body problem. For example, given two massive bodies in orbits around their common barycenter, there are five positions in space where a third body, of comparatively negligible mass, could be placed so as to maintain its position relative to the two massive bodies. As seen in a rotating reference frame that matches the angular velocity of the two co-orbiting bodies, the gravitational fields of two massive bodies combined providing the centripetal force at the Lagrange points, allowing the smaller third body to be relatively stationary with respect to the first two.


title: Lagrange point

text: The location of L is the solution to the following equation, gravitation providing the centripetal force:


title: Lagrange point

text: where "r" is the distance of the L point from the smaller object, "R" is the distance between the two main objects, and "M" and "M" are the masses of the large and small object, respectively. The quantity in parentheses on the right is the distance of L from the center of mass. Solving this for "r" involves solving a quintic function, but if the mass of the smaller object ("M") is much smaller than the mass of the larger object ("M") then and are at approximately equal distances "r" from the smaller object, equal to the radius of the Hill sphere, given by: