Human history
Human history (or world history) is the narrative of humanity's past. It is understood through archaeology, anthropology, genetics, linguistics, and (since the advent of writing) primary and secondary source documents. Humanity's written history was preceded by its prehistory, beginning with the Palaeolithic ("Old Stone Age") era. This was followed by the Neolithic ("New Stone Age") era, which saw the Agricultural Revolution begin in the Near East's Fertile Crescent between 10,000 and 5,000 BCE. During this period, humans began the systematic husbandry of plants and animals. As agriculture advanced, most humans transitioned from a nomadic to  a settled lifestyle as farmers in permanent settlements. The relative security and increased productivity provided by farming allowed communities to expand into increasingly larger units, fostered by advances in transportation. Whether in prehistoric or historic times, people always needed to be near reliable sources of drinking water. Settlements developed as early as 4,000 BCE in Iran, Mesopotamia, the Indus River valley on the Indian subcontinent, as well as on the banks of Egypt's Nile River, along China's rivers and the short rivers that flow from the Andes in the central coast of Peru. As farming developed, grain agriculture  became more sophisticated and prompted a division of labour to store food between growing seasons. Labour divisions led to the rise of a leisured upper class and the development of cities, which provided the foundation for civilization. The growing complexity of human societies necessitated systems of accounting and writing. Hinduism developed in the late Bronze Age on the Indian subcontinent. The Axial Age witnessed the introduction of religions such as Buddhism, Taoism, Confucianism, and Jainism. With civilizations flourishing, ancient history ("Antiquity," including the Classical Age and Golden Age of India, up to about 500 CE) saw the rise and fall  of empires. Post-classical history (the "Middle Ages," 500–1500 CE) witnessed the rise of Christianity, the Islamic Golden Age (c. 750 CE – c. 1258 CE), and the Timurid and European renaissances (from around 1300 CE). The mid-15th-century introduction of movable-type printing in Europe revolutionized communication and facilitated ever wider dissemination of information, hastening the end of the Middle Ages and ushering in the Scientific Revolution. The early modern period, sometimes referred to as the "European Age and Age of the Islamic Gunpowders", from about 1500 to 1800, included the Age of Discovery and the Age of Enlightenment. By  the 18th century, the accumulation of knowledge and technology had reached a critical mass that brought about the Industrial Revolution and began the late modern period, which started around 1800 and continues through the present. This scheme of historical periodization (dividing history into Antiquity, Post-Classical, Early Modern, and Late Modern periods) was developed for, and applies best to, the history of the Old World, particularly Europe and the Mediterranean. Outside this region, including Chinese and Indian civilizations, historical timelines unfolded differently up to the 18th century. By this time, due to extensive world trade and colonization, the histories of  most civilizations had become substantially intertwined. In the last quarter-millennium, the rates of growth of population, knowledge, technology, communications, commerce, weapon destructiveness, and environmental degradation have greatly accelerated, creating unprecedented opportunities and perils that now confront humanity. Prehistory ( 3.3 million years ago to 5000 years ago). Early humans. Genetic measurements indicate that the ape lineage which would lead to "Homo sapiens" diverged from the lineage that would lead to chimpanzees and bonobos, the closest living relatives of modern humans, around 4.6 to 6.2 million years ago. The Paleolithic period began with the advent of hominid tool use. Hominids, such  as "Homo erectus" had used simple wood and stone tools for millennia, but as time progressed, tools became far more refined and complex. Perhaps as early as 1.8 million years ago, but certainly by 500,000 years ago, humans began to use fire for heat and cooking. The Paleolithic also saw humans develop language, as well as a conceptual repertoire that included both the systematic burial of the dead and adornment of the living. Signs of early artistic expression can be found in the form of cave paintings and sculptures made from ivory, stone, and bone, implying a form of spirituality ; generally interpreted as either animism or shamanism. Paleolithic humans lived as hunter-gatherers, and were generally nomadic. Archaeological and genetic data suggest that source populations of Paleolithic hunter-gatherers lived in sparsely wooded areas and dispersed through areas of high primary production while avoiding dense forest cover. Anatomically modern humans first appeared in Africa approximately 300,000 years ago, achieved behavioral modernity about 50,000 years ago. and spread rapidly from Africa into the frost-free zones of Europe and Asia around 60,000 years ago. The rapid expansion of humankind to North America and Oceania took place at the climax of the  most recent ice age approximately 25,000 years ago. At the time, temperate regions of today were extremely inhospitable. Yet, by the end of the Ice Age, some 12,000 years ago, humans had colonized nearly all ice-free parts of the globe. Rise of civilization. Beginning around 10,000 BCE, the Neolithic Revolution marked the development of agriculture, which fundamentally changed the human lifestyle. Cereal crop cultivation and animal domestication had occurred in the Middle East by at least 8500 BCE in the form of wheat, barley, sheep, and goats. In the Indus Valley, crops were cultivated and cattle were domesticated by  6000 BCE. The Yellow River valley in China cultivated millet and other cereal crops by about 7000 BCE; the Yangtze valley domesticated rice earlier, by at least 8000 BCE. In the Americas, sunflowers were cultivated by about 4000 BCE, and maize and beans were domesticated in Central America by 3500 BCE. Potatoes were first cultivated in the Andes Mountains of South America, where the llama was also domesticated. Metalworking was first used in the creation of copper tools and ornaments around 6000 BCE. Gold soon followed, primarily for use in ornaments. The need for metal ores stimulated trade, as many  areas of early human settlement lacked the necessary ores. The first signs of bronze, an alloy of copper and tin, date to around 2500 BCE, but the alloy did not become widely used until much later. Agriculture created food surpluses that could support people not directly engaged in food production, permitting far denser populations and the creation of the first cities and states. Cities were centres of trade, manufacturing and political power. Cities established a symbiosis with their surrounding countrysides, absorbing agricultural products and providing, in return, manufactured goods and varying degrees of military control and protection. Early proto-cities  appeared at Jericho and Çatalhöyük around 6000 BCE. The development of cities was synonymous with the rise of civilization. Early civilizations arose first in Lower Mesopotamia (3000 BCE), followed by Egyptian civilization along the Nile River (3000 BCE), the Harappan civilization in the Indus River Valley (in present-day India and Pakistan; 2500 BCE), and Chinese civilization along the Yellow and Yangtze Rivers (2200 BCE). These societies developed a number of unifying characteristics, including a central government, a complex economy and social structure, sophisticated language and writing systems, and distinct cultures and religions. These cultures variously invented the wheel, mathematics , bronze-working, sailing boats, the potter's wheel, woven cloth, construction of monumental buildings, and writing. Writing facilitated the administration of cities, the expression of ideas, and the preservation of information. Scholars now recognize that writing may have independently developed in at least four ancient civilizations: Mesopotamia (between 3400 and 3100 BCE), Egypt (around 3250 BCE), China (2000 BCE), and lowland Mesoamerica (by 650 BCE). Typical of the Neolithic was a tendency to worship anthropomorphic deities. Entities such as the Sun, Moon, Earth, sky, and sea were often deified. Shrines developed, which evolved into temple establishments, complete with a complex  hierarchy of priests and priestesses and other functionaries. Among the earliest surviving written religious scriptures are the Egyptian "Pyramid Texts", the oldest of which date to between 2400 and 2300 BCE. Ancient history (3000 BCE to 500 CE). Cradles of civilization. The Bronze Age is part of the three-age system (Stone Age, Bronze Age, Iron Age), a system which effectively describes the early history of civilization for some parts of the world. The Bronze Age saw the development of city-states as well as the emergence of first civilizations. These settlements were concentrated in fertile river valleys: the Tigris  and Euphrates in Mesopotamia, the Nile in Egypt, the Indus in the Indian subcontinent, and the Yangtze and Yellow Rivers in China. Sumer, located in Mesopotamia, is the first known complex civilization, having developed the first city-states in the 4th millennium BCE. It was in these cities that the earliest known form of writing, cuneiform script, appeared around 3000 BCE. Cuneiform writing began as a system of pictographs, whose pictorial representations eventually became simplified and more abstract. Cuneiform texts were written by using a blunt reed as a stylus to draw symbols upon clay tablets. Writing made the administration  of a large state far easier. Transport was facilitated by waterways—by rivers and seas. The Mediterranean Sea, at the juncture of three continents, fostered the projection of military power and the exchange of goods, ideas, and inventions. This era also saw new land technologies, such as horse-based cavalry and chariots, that allowed armies to move faster. These developments led to the rise of territorial states and empires. In Mesopotamia there prevailed a pattern of independent warring city-states and of a loose hegemony shifting from one city to another. In Egypt, by contrast, first there was a dual  division into Upper and Lower Egypt which was shortly followed by unification of all the valley around 3100 BCE, followed by permanent pacification. In Crete the Minoan civilization had entered the Bronze Age by 2700 BCE and is regarded as the first civilization in Europe. Over the next millennia, other river valleys saw monarchical empires rise to power. In the 25th – 21st centuries BCE, the empires of Akkad and Sumer arose in Mesopotamia. Over the following millennia, civilizations developed across the world. Trade increasingly became a source of power as states with access to important resources or controlling important trade  routes rose to dominance. By 1600 BCE, Mycenaean Greece began to develop, and ended with the Late Bronze Age collapse that started to affect many Mediterranean civilizations between 1200 and 1150 BCE. In India, this era was the Vedic period (1750-600 BCE), which laid the foundations of Hinduism and other cultural aspects of early Indian society, and ended in the 6th century BCE. From around 550 BCE, many independent kingdoms and republics known as the Mahajanapadas were established across the subcontinent. As complex civilizations arose in the Eastern Hemisphere, the indigenous societies in the Americas remained relatively simple and  fragmented into diverse regional cultures. During the formative stage in Mesoamerica (about 1500 BCE to 500 CE), more complex and centralized civilizations began to develop, mostly in what is now Mexico, Central America, and Peru. They included civilizations such as the Olmecs, Maya, Zapotecs, Moche, and Nazca. They developed agriculture, growing maize, chili peppers, cocoa, tomatoes, and potatoes, crops unique to the Americas, and creating distinct cultures and religions. These ancient indigenous societies would be greatly affected, for good and ill, by European contact during the early modern period. Axial Age. Beginning in the 8th century BCE, the "Axial Age  saw the development of a set of transformative philosophical and religious ideas, mostly independently, in many different places. Chinese Confucianism, Indian Buddhism and Jainism, and Jewish monotheism are all claimed by some scholars to have developed in the 6th century BCE. (Karl Jaspers' Axial-Age theory also includes Persian Zoroastrianism, but other scholars dispute his timeline for Zoroastrianism.) In the 5th century BCE, Socrates and Plato made substantial advances in the development of ancient Greek philosophy. In the East, three schools of thought would dominate Chinese thinking well into the 20th century. These were Taoism, Legalism, and Confucianism. The Confucian 	Human history
28062312	tradition, which would become particularly dominant, looked for political morality not to the force of law but to the power and example of tradition. Confucianism would later spread to Korea and toward Japan. In the West, the Greek philosophical tradition, represented by Socrates, Plato, Aristotle, and other philosophers, along with accumulated science, technology, and culture, diffused throughout Europe, Egypt, the Middle East, and Northwest India, starting in the 4th century BCE after the conquests of Alexander the Great of Macedon. Regional empires. The millennium from 500 BCE to 500 CE saw a series of empires of unprecedented size develop. Well	Human history
28062313	-trained professional armies, unifying ideologies, and advanced bureaucracies created the possibility for emperors to rule over large domains whose populations could attain numbers upwards of tens of millions of subjects. The great empires depended on military annexation of territory and on the formation of defended settlements to become agricultural centres. The relative peace that the empires brought encouraged international trade, most notably the massive trade routes in the Mediterranean, the maritime trade web in the Indian Ocean, and the Silk Road. In southern Europe, the Greeks (and later the Romans), in an era known as classical antiquity," established cultures whose  practices, laws, and customs are considered the foundation of contemporary Western culture. There were a number of regional empires during this period. The kingdom of the Medes helped to destroy the Assyrian Empire in tandem with the nomadic Scythians and the Babylonians. Nineveh, the capital of Assyria, was sacked by the Medes in 612 BCE. The Median Empire gave way to successive Iranian empires, including the Achaemenid Empire (550–330 BCE), the Parthian Empire (247 BCE–224 CE), and the Sasanian Empire (224–651 CE). Several empires began in modern-day Greece. First was the Delian League (from 477 BCE) and the succeeding  Athenian Empire (454–404 BCE), centered in present-day Greece. Later, Alexander the Great (356–323 BCE), of Macedon, founded an empire of conquest, extending from present-day Greece to present-day India. The empire divided shortly after his death, but the influence of his Hellenistic successors made for an extended Hellenistic period (323–31 BCE) throughout the region. In Asia, the Maurya Empire (322–185 BCE) existed in present-day India; in the 3rd century BCE, most of South Asia was united to the Maurya Empire by Chandragupta Maurya and flourished under Ashoka the Great. From the 3rd century CE, the Gupta dynasty  oversaw the period referred to as ancient India's Golden Age. From the 4th to 6th centuries, northern India was ruled by the Gupta Empire. In southern India, three prominent Dravidian kingdoms emerged: the Cheras, Cholas, and Pandyas. The ensuing stability contributed to heralding in the golden age of Hindu culture in the 4th and 5th centuries. In Europe, the Roman Empire, centered in present-day Italy, began in the 7th century BCE. In the 3rd century BCE the Roman Republic began expanding its territory through conquest and alliances. By the time of Augustus (63 BCE – 14 CE), the first  Roman Emperor, Rome had already established dominion over most of the Mediterranean. The empire would continue to grow, controlling much of the land from England to Mesopotamia, reaching its greatest extent under the emperor Trajan (died 117 CE). In the 3rd century CE, the empire split into western and eastern regions, with (usually) separate emperors. The Western empire would fall, in 476 CE, to German influence under Odoacer. The eastern empire, now known as the Byzantine Empire, with its capital at Constantinople, would continue for another thousand years, until Constantinople was conquered by the Ottoman Empire in 1453. During most  of its existence, the Byzantine Empire was one of the most powerful economic, cultural, and military forces in Europe. And Constantinople is generally considered to be the center of "Eastern Orthodox civilization". Although the Roman state continued and its traditions were maintained, modern historians distinguish Byzantium from its earlier incarnation because it was centred on Constantinople, oriented towards Greek rather than Latin culture, and characterised by Eastern Orthodox Christianity. In China, the Qin dynasty (221–206 BCE), the first imperial dynasty of China, was followed by the Han Empire (206 BCE – 220 CE). The Han dynasty was comparable in power and  influence to the Roman Empire that lay at the other end of the Silk Road. Han China developed advanced cartography, shipbuilding, and navigation. The Chinese invented blast furnaces, and created finely tuned copper instruments. As with other empires during the Classical Period, Han China advanced significantly in the areas of government, education, mathematics, astronomy, technology, and many others. In Africa, the Kingdom of Aksum, centred in present-day Ethiopia, established itself by the 1st century CE as a major trading empire, dominating its neighbours in South Arabia and Kush and controlling the Red Sea trade. It minted its own currency  and carved enormous monolithic steles such as the Obelisk of Axum to mark their emperors' graves. Successful regional empires were also established in the Americas, arising from cultures established as early as 2500 BCE. In Mesoamerica, vast pre-Columbian societies were built, the most notable being the Zapotec Empire (700 BCE – 1521 CE), and the Maya civilization, which reached its highest state of development during the Mesoamerican Classic period (c. 250–900 CE), but continued throughout the Post-Classic period until the arrival of the Spanish in the 16th century CE. Maya civilization arose as the Olmec mother culture gradually declined . The great Mayan city-states slowly rose in number and prominence, and Maya culture spread throughout the Yucatán and surrounding areas. The later empire of the Aztecs was built on neighbouring cultures and was influenced by conquered peoples such as the Toltecs. Some areas experienced slow but steady technological advances, with important developments such as the stirrup and moldboard plough arriving every few centuries. There were, however, in some regions, periods of rapid technological progress. Most important, perhaps, was the Hellenistic period in the region of the Mediterranean, during which hundreds of technologies were invented. Such periods were followed by  periods of technological decay, as during the Roman Empire's decline and fall and the ensuing early medieval period. Declines, falls, and resurgence. The ancient empires faced common problems associated with maintaining huge armies and supporting a central bureaucracy. These costs fell most heavily on the peasantry, while land-owning magnates increasingly evaded centralized control and its costs. Barbarian pressure on the frontiers hastened internal dissolution. China's Han dynasty fell into civil war in 220 CE, beginning the Three Kingdoms period, while its Roman counterpart became increasingly decentralized and divided about the same time in what is known as  the Crisis of the Third Century. The great empires of Eurasia were all located on temperate and subtropical coastal plains. From the Central Asian steppes, horse-based nomads, mainly Mongols and Turks, dominated a large part of the continent. The development of the stirrup and the breeding of horses strong enough to carry a fully armed archer made the nomads a constant threat to the more settled civilizations. The gradual break-up of the Roman Empire, spanning several centuries after the 2nd century CE, coincided with the spread of Christianity outward from the Middle East. The Western Roman Empire fell  under the domination of Germanic tribes in the 5th century, and these polities gradually developed into a number of warring states, all associated in one way or another with the Catholic Church. The remaining part of the Roman Empire, in the eastern Mediterranean, continued as what came to be called the Byzantine Empire. Centuries later, a limited unity would be restored to western Europe through the establishment in 962 of a revived "Roman Empire", later called the Holy Roman Empire, comprising a number of states in what is now Germany, Austria, Switzerland, Czech Republic, Belgium, Italy, and parts of France . In China, dynasties would rise and fall, but, by sharp contrast to the Mediterranean-European world, dynastic unity would be restored. After the fall of the Eastern Han dynasty and the demise of the Three Kingdoms, nomadic tribes from the north began to invade in the 4th century, eventually conquering areas of northern China and setting up many small kingdoms. The Sui dynasty successfully reunified the whole of China in 581, and laid the foundations for a Chinese golden age under the Tang dynasty (618–907). Post-classical history (500 CE to 1500 CE). The term "post-classical era", though derived  from the name of the era of "classical antiquity", takes in a broader geographic sweep. The era is commonly dated from the 5th-century fall of the Western Roman Empire, which fragmented into many separate kingdoms, some of which would later be confederated under the Holy Roman Empire. The Byzantine Empire survived until late in the post-classical or medieval period. The post-classical period also encompasses the Early Muslim conquests, the subsequent Islamic Golden Age, and the commencement and expansion of the Arab slave trade, followed by the Mongol invasions of the Middle East, Central Asia, and Eastern Europe  and the founding around 1280 of the Ottoman Empire. South Asia saw a series of middle kingdoms of India, followed by the establishment of Islamic empires in India. In western Africa, the Mali Empire and the Songhai Empire developed. On the southeast coast of Africa, Arabic ports were established where gold, spices, and other commodities were traded. This allowed Africa to join the Southeast Asia trading system, bringing it contact with Asia; this, along with Muslim culture, resulted in the Swahili culture. China experienced the successive Sui, Tang, Song, Yuan, and early Ming dynasties. Middle Eastern trade routes along the  Indian Ocean, and the Silk Road through the Gobi Desert, provided limited economic and cultural contact between Asian and European civilizations. During the same period, civilizations in the Americas, such as the Mississippian culture, Ancestral Puebloans, Wari and Inca, Maya, and Aztecs, reached their zenith. All would be compromised by, then conquered after, contact with European colonists at the beginning of the modern period. Greater Middle East. Prior to the advent of Islam in the 7th century, the Middle East was dominated by the Byzantine Empire and the Sasanian Empire that frequently fought each other for control of several disputed  regions. This was also a cultural battle, with the Byzantine Christian culture competing against Persian Zoroastrian traditions. The birth of the Islam created a new contender that quickly surpassed both of these empires. The new religion greatly affected the political, economic, and military history of the Old World, especially the Middle East. From their centre on the Arabian Peninsula, Muslims began their expansion during the early Postclassical Era. By 750 CE, they came to conquer most of the Near East, North Africa, and parts of Europe, ushering in an era of learning, science, and invention known as the Islamic Golden  Age. The knowledge and skills of the ancient Near East, Greece, and Persia were preserved in the Postclassical Era by Muslims, who also added new and important innovations from outside, such as the manufacture of paper from China and decimal positional numbering from India. Much of this learning and development can be linked to geography. Even prior to Islam's presence, the city of Mecca had served as a centre of trade in Arabia, and the Islamic prophet Muhammad himself was a merchant. With the new Islamic tradition of the "Hajj", the pilgrimage to Mecca, the city became even more  a centre for exchanging goods and ideas. The influence held by Muslim merchants over African-Arabian and Arabian-Asian trade routes was tremendous. As a result, Islamic civilization grew and expanded on the basis of its merchant economy, in contrast to the Europeans, Indians, and Chinese, who based their societies on an agricultural landholding nobility. Merchants brought goods and their Islamic faith to China, India, Southeast Asia, and the kingdoms of western Africa, and returned with new discoveries and inventions. The Crusading movement initially developed religious motivations and European expansionism to roll back Muslim territory and regain control of the  Holy Land. It was ultimately unsuccessful and served more to weaken the Byzantine Empire, especially with the 1204 Sack of Constantinople. The Byzantine Empire began to lose increasing amounts of territory to the Ottoman Turks. Arab domination of the region ended in the mid-11th century with the arrival of the Seljuq Turks, migrating south from the Turkic homelands in Central Asia. In the early 13th century, a new wave of invaders, the Mongol Empire, swept through the region but were eventually eclipsed by the Turks and the founding of the Ottoman Empire in modern-day Turkey around 1280. North Africa  saw the rise of polities formed by the Berbers, such as the Marinid dynasty in Morocco, the Zayyanid dynasty in Algeria, and the Hafsid dynasty in Tunisia. The coastal region was known as the Barbary Coast. Pirates based in North African ports conducted operations that included capturing merchant ships and raiding coastal settlements. Many European captives were sold in North African markets as part of the Barbary slave trade. Starting with the Sui dynasty (581–618), the Chinese began expanding into eastern Central Asia, and confronted Turkic nomads, who were becoming the most dominant ethnic group in Central Asia. Originally the  relationship was largely cooperative, but in 630 the Tang dynasty began an offensive against the Turks, capturing areas of the Mongolian Ordos Desert. In the 8th century, Islam began to penetrate the region and soon became the sole faith of most of the population, though Buddhism remained strong in the east. The desert nomads of Arabia could militarily match the nomads of the steppe, and the early Arab Empire gained control over parts of Central Asia. The Hephthalites were the most powerful of the nomad groups in the 6th and 7th centuries, and controlled much of the region. In the  9th through 13th centuries the region was divided among several powerful states, including the Samanid Empire, the Seljuk Empire, and the Khwarezmid Empire. The largest empire to rise out of Central Asia developed when Genghis Khan united the tribes of Mongolia. The Mongol Empire spread to comprise all of Central Asia and China as well as large parts of Russia and the Middle East.} After Genghis Khan died in 1227, most of Central Asia continued to be dominated by a successor state, Chagatai Khanate. In 1369, Timur, a Turkic leader in the Mongol military tradition, conquered most of the region  and founded the Timurid Empire. Timur's large empire collapsed soon after his death, however. The region then became divided into smaller khanates that were established by the Uzbeks, including the Khanate of Bukhara and the Khanate of Khiva. In the aftermath of the Byzantine–Sasanian wars, the Caucasus saw Armenia and Georgia flourish as independent realms free from foreign suzerainty. As the Byzantines and Sasanians became exhausted of continuous wars, the Rashidun Caliphate used the opportunity to expand to the Caucasus during the early Muslim conquests. By the 13th century, the arrival of the Mongols saw the region invaded  once again. Europe. Since at least the 4th century, Christianity, primarily the Roman Catholic Church, and later Protestantism, has played a prominent role in the shaping of Western civilization. Europe during the Early Middle Ages was characterized by depopulation, deurbanization, and barbarian invasion, all of which had begun in late antiquity. The barbarian invaders formed their own new kingdoms in the remains of the Western Roman Empire. In the 7th century, North Africa and the Middle East, once part of the Eastern Roman Empire, became part of the Caliphate after conquest by Muhammad's successors. Although there were substantial changes  in society and political structures, most of the new kingdoms incorporated as many of the existing Roman institutions as they could. Christianity expanded in western Europe, and monasteries were founded. In the 7th and 8th centuries the Franks, under the Carolingian dynasty, established an empire covering much of western Europe; it lasted until the 9th century, when it succumbed to pressure from new invaders—the Vikings, Magyars, and Saracens. During the High Middle Ages, which began after 1000, the population of Europe increased greatly as technological and agricultural innovations allowed trade to flourish and crop yields to increase. Manorialism, the  organization of peasants into villages that owed rents and labour service to nobles, and feudalism, a political structure whereby knights and lower-status nobles owed military service to their overlords in return for the right to rents from lands and manors, were two of the ways of organizing medieval society that developed during the High Middle Ages. Kingdoms became more centralized after the decentralizing effects of the break-up of the Carolingian Empire. In 1054 AD the Great Schism between the Roman Catholic Church and the Eastern Orthodox Church led to the prominent cultural differences between Western and Eastern Europe . The Crusading movement attempted to gain Roman Catholic control of the Holy Land from the Muslims and succeeded for long enough to establish some Christian states in the Near East. Italian merchants imported slaves to work in households or in sugar processing. Intellectual life was marked by scholasticism and the founding of universities, while the building of Gothic cathedrals and churches was one of the outstanding artistic achievements of the age. The Late Middle Ages were marked by difficulties and calamities. Famine, plague, and war devastated the population of western Europe. The Black Death alone killed approximately 75 to 200  million people between 1347 and 1350. It was one of the deadliest pandemics in human history. Starting in Asia, the disease reached Mediterranean and western Europe during the late 1340s, and killed tens of millions of Europeans in six years; between a third and a half of the population perished. The Middle Ages witnessed the first sustained urbanization of northern and western Europe and it lasted until the beginning of the early modern period in the 16th century, marked by the rise of nation states, the division of Western Christianity in the Reformation, the rise of humanism in the Italian  Renaissance, and the beginnings of European overseas expansion which allowed for the Columbian exchange. In Central and Eastern Europe, in 1386, the Kingdom of Poland and the Grand Duchy of Lithuania (the latter including territories of modern Belarus and Ukraine), facing depredations by the Teutonic Order and later also threats from Muscovy, the Crimean Tatars, and the Ottoman Empire, formed a personal union through the marriage of Poland's Queen Jadwiga to Lithuanian Grand Duke Jogaila, who became King Władysław II Jagiełło of Poland. For the next four centuries, until the 18th-century partitions of the Polish-Lithuanian Commonwealth by  Prussia, Russia, and Austria, the two polities conducted a federated condominium, long Europe's largest state, which welcomed diverse ethnicities and religions, including most of the world's Jews, furthered scientific thought (e.g. Nicolaus Copernicus's heliocentric theory). Sub-Saharan Africa. Medieval sub-Saharan Africa was home to many different civilizations. The Kingdom of Aksum declined in the 7th century as Islam cut it off from its Christian allies and its people moved further into the Ethiopian Highlands for protection. They eventually gave way to the Zagwe dynasty who are famed for their rock cut architecture at Lalibela. The Zagwe  would then fall to the Solomonic dynasty who claimed descent from the Aksumite emperors and would rule the country well into the 20th century. In the West African Sahel region, many Islamic empires rose, such as the Ghana Empire, the Mali Empire, the Songhai Empire, and the Kanem–Bornu Empire. They controlled the trans-Saharan trade in gold, ivory, salt and slaves. South of the Sahel, civilizations rose in the coastal forests. These include the Yoruba city of Ifẹ, noted for its art, and the Oyo Empire, the Kingdom of Benin of the Edo people centred in Benin City, the  Igbo Kingdom of Nri which produced advanced bronze art at Igbo-Ukwu, and the Akan who are noted for their intricate architecture. Central Africa saw the formation of several states, including the Kingdom of Kongo. In what is now modern Southern Africa, native Africans created various kingdoms such as the Kingdom of Mutapa. They flourished through trade with the Swahili people on the East African coast. They built large defensive stone structures without mortar such as Great Zimbabwe, capital of the Kingdom of Zimbabwe, Khami, capital of Kingdom of Butua, and Danangombe (Dhlo-Dhlo), capital of the Rozvi Empire. The  Swahili people themselves were the inhabitants of the East African coast from Kenya to Mozambique who traded extensively with Asians and Arabs, who introduced them to Islam. They built many port cities such as Mombasa, Zanzibar and Kilwa, which were known to Chinese sailors under Zheng He and Islamic geographers. South Asia. In northern India, after the fall (550 CE) of the Gupta Empire, the region was divided into a complex and fluid network of smaller kingly states. Early Muslim incursions began in the west in 712 CE, when the Arab Umayyad Caliphate annexed much of present-day Pakistan. Arab  military advance was largely halted at that point, but Islam still spread in India, largely due to the influence of Arab merchants along the western coast. The ninth century saw a Tripartite Struggle for control of northern India, among the Pratihara Empire, the Pala Empire, and the Rashtrakuta Empire. Some of the important states that emerged in India at this time included the Bahmani Sultanate and the Vijayanagara Empire. Post-classical dynasties in South India included those of the Chalukyas, the Hoysalas, the Cholas, the Mughals, the Marathas, and the Mysores. Science, engineering, art, literature, astronomy, and philosophy flourished under  the patronage of these kings. Northeast Asia. After a period of relative disunity, China was reunified by the Sui dynasty in 589 and under the succeeding Tang dynasty (618–907) China entered a Golden Age. The Tang Empire competed with the Tibetan Empire (618–842) for control of areas in Inner and Central Asia. The Tang dynasty eventually splintered, however, and after half a century of turmoil the Song dynasty reunified China, when it was, according to William McNeill, the "richest, most skilled, and most populous country on earth". Pressure from nomadic empires to the north became increasingly urgent. By 1142, North  China had been lost to the Jurchens in the Jin–Song Wars, and the Mongol Empire conquered all of China in 1279, along with almost half of Eurasia's landmass. After about a century of Mongol Yuan dynasty rule, the ethnic Chinese reasserted control with the founding of the Ming dynasty (1368). In Japan, the imperial lineage had been established by this time, and during the Asuka period (538–710) the Yamato Province developed into a clearly centralized state. Buddhism was introduced, and there was an emphasis on the adoption of elements of Chinese culture and Confucianism. The Nara period of  the 8th century marked the emergence of a strong Japanese state and is often portrayed as a golden age. During this period, the imperial government undertook great public works, including government offices, temples, roads, and irrigation systems. The Heian period (794 to 1185) saw the peak of imperial power, followed by the rise of militarized clans, and the beginning of Japanese feudalism. The feudal period of Japanese history, dominated by powerful regional lords (daimyos) and the military rule of warlords (shoguns) such as the Ashikaga shogunate and Tokugawa shogunate, stretched from 1185 to 1868. The emperor remained, but mostly as  a figurehead, and the power of merchants was weak. Postclassical Korea saw the end of the Three Kingdoms era, the three kingdoms being Goguryeo, Baekje and Silla. Silla conquered Baekje in 660, and Goguryeo in 668, marking the beginning of the Northern and Southern States period (남북국시대), with Unified Silla in the south and Balhae, a successor state to Goguryeo, in the north. In 892 CE, this arrangement reverted to the Later Three Kingdoms, with Goguryeo (then called Taebong and eventually named Goryeo) emerging as dominant, unifying the entire peninsula by 936. The founding Goryeo dynasty ruled until 1392, succeeded  by the Joseon dynasty, which ruled for approximately 500 years. Southeast Asia. The beginning of the Middle Ages in Southeast Asia saw the fall (550 CE) of the Kingdom of Funan to the Chenla Empire, which was then replaced by the Khmer Empire (802 CE). The Khmer people's capital city, Angkor, was the largest city in the world prior to the industrial age and contained over a thousand temples, the most famous being Angkor Wat. The Sukhothai (1238 CE) and Ayutthaya (1351 CE) kingdoms were major powers of the Thai people, who were influenced by the Khmer. Starting in  the 9th century, the Pagan Kingdom rose to prominence in modern Myanmar. Its collapse brought about political fragmention that ended with the rise of the Toungoo Empire in the 16th century. Other notable kingdoms of the period include the Srivijayan Empire and the Lavo Kingdom (both coming into prominence in the 7th century), the Champa and the Hariphunchai (both about 750), the Đại Việt (968), Lan Na (13th century), Majapahit (1293), Lan Xang (1354), and the Kingdom of Ava (1364). This period saw the spread of Islam to present-day Indonesia (beginning in the 13th century) and the emergence of  the Malay states, including the Malacca Sultanate and the Bruneian Empire. In the Philippines, several polities were formed such as the Rajahnate of Maynila, the Rajahnate of Cebu, and the Rajahnate of Butuan. Oceania. In Oceania, the Tuʻi Tonga Empire was founded in the 10th century CE and expanded between 1200 and 1500. Tongan culture, language, and hegemony spread widely throughout Eastern Melanesia, Micronesia, and Central Polynesia during this period, influencing East 'Uvea, Rotuma, Futuna, Samoa, and Niue, as well as specific islands and parts of Micronesia (Kiribati, Pohnpei, and miscellaneous outliers), Vanuatu, and New Caledonia (specifically, the Loyalty Islands , with the main island being predominantly populated by the Melanesian Kanak people and their cultures). In northern Australia, there is evidence that some aboriginal groups regularly traded with Makassarese fishermen from Indonesia before the arrival of Europeans. At around the same time, a powerful thalassocracy appeared in Eastern Polynesia, centered around the Society Islands, specifically on the sacred Taputapuatea marae, which drew in Eastern Polynesian colonists from places as far away as Hawaii, New Zealand ("Aotearoa"), and the Tuamotu Islands for political, spiritual and economic reasons, until the unexplained collapse of regular long-distance voyaging in the Eastern Pacific a  few centuries before Europeans began exploring the area. Indigenous written records from this period are virtually nonexistent, as it seems that all Pacific Islanders, with the possible exception of the enigmatic Rapa Nui and their currently undecipherable Rongorongo script, had no writing systems of any kind until after their introduction by European colonists. However, some indigenous prehistories can be estimated and academically reconstructed through careful, judicious analysis of native oral traditions, colonial ethnography, archeology, physical anthropology, and linguistics research. Americas. In North America, this period saw the rise of the Mississippian culture in the modern-day United States c. 800  CE, marked by the extensive 12th-century urban complex at Cahokia. The Ancestral Puebloans and their predecessors (9th – 13th centuries) built extensive permanent settlements, including stone structures that would remain the largest buildings in North America until the 19th century. In Mesoamerica, the Teotihuacan civilization fell and the Classic Maya collapse occurred. The Aztec Empire came to dominate much of Mesoamerica in the 14th and 15th centuries. In South America, the 14th and 15th centuries saw the rise of the Inca. The Inca Empire of Tawantinsuyu, with its capital at Cusco, spanned the entire Andes, making it the most extensive  pre-Columbian civilization. The Inca were prosperous and advanced, known for an excellent road system and unrivaled masonry. Modern history (1500 to the present). In the linear, global, historiographical approach, modern history (the "modern period," the "modern era," "modern times") is the history of the period following post-classical history (in Europe known as the "Middle Ages"), spanning from about 1500 to the present. "Contemporary history" includes events from around 1945 to the present. (The definitions of both terms, "modern history" and "contemporary history", have changed over time, as more history has occurred, and so have their start dates.) Modern  history can be further broken down into periods: The defining features of the modern era developed predominantly in Europe, and so different periodizations are sometimes applied to other parts of the world. When the European periods are used globally, this is often in the context of contact with European culture in the Age of Discovery. In the humanities and social sciences, the norms, attitudes, and practices arising during the modern period are known as modernity. The corresponding terms for post-World War II culture are postmodernity or late modernity. Early modern period (1500 to 1800). The "early Modern period" was  the period between the Middle Ages and the Industrial Revolution—roughly 1500 to 1800. The early Modern period was characterized by the rise of science, and by increasingly rapid technological progress, secularized civic politics, and the nation state. Capitalist economies began their rise, initially in northern Italian republics such as Genoa. The Early Modern period saw the rise and dominance of mercantilist economic theory, and the decline and eventual disappearance, in much of the European sphere, of feudalism, serfdom, and the power of the Catholic Church. The period included the Reformation, the disastrous Thirty Years' War, the Age of Discovery , European colonial expansion, the peak of European witch-hunting, the Scientific Revolution, and the Age of Enlightenment. During the Early modern period, Protestantism eventually became the majority faith throughout northwestern Europe and in England and English-speaking America, and have developed their own culture, with major contributions in education, the humanities and sciences, the political and social order, the economy and the arts and many other fields. Renaissance. Europe's Renaissance – the "rebirth" of classical culture, beginning in the 14th century and extending into the 16th – comprised the rediscovery of the classical world's cultural, scientific, and technological achievements, and  the economic and social rise of Europe. The Renaissance engendered a culture of inquisitiveness which ultimately led to Humanism and the Scientific Revolution. This period, which saw social and political upheavals, and revolutions in many intellectual pursuits, is also celebrated for its artistic developments and the attainments of such polymaths as Leonardo da Vinci and Michelangelo, who inspired the term "Renaissance man." European expansion. During this period, European powers came to dominate most of the world. Although the most developed regions of European classical civilization were more urbanized than any other region of the world, European civilization had undergone a  lengthy period of gradual decline and collapse. During the early modern period, Europe was able to regain its dominance; historians still debate the causes. Europe's success in this period stands in contrast to other regions. For example, one of the most advanced civilizations of the Middle Ages was China. It had developed an advanced monetary economy by 1000 CE. China had a free peasantry who were no longer subsistence farmers, and could sell their produce and actively participate in the market. According to Adam Smith, writing in the 18th century, China had long been one of the richest, most  fertile, best cultivated, most industrious, most urbanized, and most prosperous countries in the world. It enjoyed a technological advantage and had a monopoly in cast iron production, piston bellows, suspension bridge construction, printing, and the compass. However, it seemed to have long since stopped progressing. Marco Polo, who visited China in the 13th century, describes its cultivation, industry, and populousness almost in the same terms as travellers would in the 18th century. One theory of Europe's rise holds that Europe's geography played an important role in its success. The Middle East, India and China are all ringed by  mountains and oceans but, once past these outer barriers, are nearly flat. By contrast, the Pyrenees, Alps, Apennines, Carpathians and other mountain ranges run through Europe, and the continent is also divided by several seas. This gave Europe some degree of protection from the peril of Central Asian invaders. Before the era of firearms, these nomads were militarily superior to the agricultural states on the periphery of the Eurasian continent and, as they broke out into the plains of northern India or the valleys of China, were all but unstoppable. These invasions were often devastating. The Golden Age of Islam  was ended by the Mongol sack of Baghdad in 1258. India and China were subject to periodic invasions, and Russia spent a couple of centuries under the Mongol-Tatar yoke. Central and western Europe, logistically more distant from the Central Asian heartland, proved less vulnerable to these threats. Geography contributed to important geopolitical differences. For most of their histories, China, India, and the Middle East were each unified under a single dominant power that expanded until it reached the surrounding mountains and deserts. In 1600 the Ottoman Empire controlled almost all the Middle East, the Ming dynasty ruled China, and  the Mughal Empire held sway over India. By contrast, Europe was almost always divided into a number of warring states. Pan-European empires, with the notable exception of the Roman Empire, tended to collapse soon after they arose. Another doubtless important geographic factor in the rise of Europe was the Mediterranean Sea, which, for millennia, had functioned as a maritime superhighway fostering the exchange of goods, people, ideas and inventions. Nearly all the agricultural civilizations have been heavily constrained by their environments. Productivity remained low, and climatic changes easily instigated boom-and-bust cycles that brought about civilizations' rise and  fall. By about 1500, however, there was a qualitative change in world history. Technological advance and the wealth generated by trade gradually brought about a widening of possibilities. Many have also argued that Europe's institutions allowed it to expand, that property rights and free market economics were stronger than elsewhere due to an ideal of freedom peculiar to Europe. In recent years, however, scholars such as Kenneth Pomeranz have challenged this view. Europe's maritime expansion unsurprisingly—given the continent's geography—was largely the work of its Atlantic states: Portugal, Spain, England, France, and the Netherlands. Initially the  Portuguese and Spanish Empires were the predominant conquerors and sources of influence, and their union resulted in the Iberian Union, the first global empire on which the "sun never set". By the late 16th century, silver from the Americas accounted for the Spanish empire's wealth. Soon the more northern English, French and Dutch began to dominate the Atlantic. In a series of wars fought in the 17th and 18th centuries, culminating with the Napoleonic Wars, Britain emerged as the new world power. Regional developments. Greater Middle East. The Ottoman Empire, after conquering Constantinople in 1453, quickly became the most  powerful state in the Middle East. Persia came under the rule of the Safavid Empire in 1501, succeeded by the Afsharid Empire in 1736, the Zand Empire in 1751, and the Qajar Empire in 1794. In North Africa, the Wattasid Sultanate, Zayyanid Sultanate, and Hafsid Sultanate remained as independent Berber states until the 16th century. Areas to the north and east in Central Asia were held by the Uzbeks and Pashtuns. By the start of the 19th century, the Russian Empire began its conquest of the Caucasus. Europe. In Russia, Ivan the Terrible was crowned in 1547 as the first  Tsar of Russia, and by annexing the Turkic khanates in the east, transformed Russia into a regional power. The countries of western Europe, while expanding prodigiously through technological advancement and colonial conquest, competed with each other economically and militarily in a state of almost constant . Often the wars had a religious dimension, either Catholic versus Protestant, or (primarily in eastern Europe) Christian versus Muslim. Wars of particular note include the Thirty Years' War, the War of the Spanish Succession, the Seven Years' War, and the French Revolutionary Wars. Napoleon came to power in France in 1799, an event foreshadowing the  Napoleonic Wars of the early 19th century. Sub-Saharan Africa. In Africa, this period saw a decline in many civilizations and an advancement in others. The Swahili coast declined after coming under the Portuguese Empire and later the Omani Empire. In West Africa, the Songhai Empire fell to the Moroccans in 1591 when they invaded with guns. The Bono State which gave birth to numerous Akan states in search of gold such as Akwamu, Akyem, Fante, Adansi etc. The South African Kingdom of Zimbabwe gave way to smaller kingdoms such as Mutapa, Butua, and Rozvi. Ethiopia suffered from the 1531  invasion from neighbouring Muslim Adal Sultanate, and in 1769 entered the Zemene Mesafint (Age of Princes) during which the Emperor became a figurehead and the country was ruled by warlords, though the royal line later would recover under Emperor Tewodros II. The Ajuran Sultanate, in the Horn of Africa, began to decline in the 17th century, succeeded by the Geledi Sultanate. Other civilizations in Africa advanced during this period. The Oyo Empire experienced its golden age, as did the Kingdom of Benin. The Ashanti Empire rose to power in what is modern day Ghana in 1670. The Kingdom of Kongo  also thrived during this period. South Asia. On the Indian subcontinent, the Delhi Sultanate and the Deccan sultanates would give way, beginning in the 16th century, to the Mughal Empire. Starting in the northwest, the Mughal Empire would by the late 17th century come to rule the entire subcontinent, except for the southernmost Indian provinces, which would remain independent. Against the Muslim Mughal Empire, the Hindu Maratha Empire was founded on the west coast in 1674, gradually gaining territory—a majority of present-day India—from the Mughals over several decades, particularly in the Mughal–Maratha Wars (1681–1701). The Maratha  Empire would in 1818 fall under the control of the British East India Company, with all former Maratha and Mughal authority devolving in 1858 to the British Raj. Northeast Asia. In China, the Ming gave way in 1644 to the Qing, the last Chinese imperial dynasty, which would rule until 1912. Japan experienced its Azuchi–Momoyama period (1568–1603), followed by the Edo period (1603–1868). The Korean Joseon dynasty (1392–1910) ruled throughout this period, successfully repelling 16th and 17th century invasions from Japan and China. Expanded maritime trade with Europe significantly affected China and Japan during this period, particularly by the  Portuguese who had a presence in Macau and Nagasaki. However, China and Japan would later pursue isolationist policies designed to eliminate foreign influences. Southeast Asia. In 1511 the Portuguese overthrew the Malacca Sultanate in present-day Malaysia and Indonesian Sumatra. The Portuguese held this important trading territory (and the valuable associated navigational strait) until overthrown by the Dutch in 1641. The Johor Sultanate, centred on the southern tip of the Malay Peninsula, became the dominant trading power in the region. European colonization expanded with the Dutch in Indonesia, the Portuguese in East Timor, and the Spanish in the Philippines. Into  the 19th century, European expansion would affect the whole of Southeast Asia, with the British in Myanmar and Malaysia, and the French in Indochina. Only Thailand would successfully resist colonization. Oceania. The Pacific islands of Oceania would also be affected by European contact, starting with the circumnavigational voyage of Ferdinand Magellan, who landed on the Marianas and other islands in 1521. Also notable were the voyages (1642–44) of Abel Tasman to present-day Australia, New Zealand and nearby islands, and the voyages (1768–1779) of Captain James Cook, who made the first recorded European contact with Hawaii. Britain would found its  first colony on Australia in 1788. Americas. In the Americas, the western European powers vigorously colonized the newly discovered continents, largely displacing the indigenous populations, and destroying the advanced civilizations of the Aztecs and the Incas. Spain, Portugal, Britain, and France all made extensive territorial claims, and undertook large-scale settlement, including the importation of large numbers of African slaves. Portugal claimed Brazil. Spain claimed the rest of South America, Mesoamerica, and southern North America. Britain colonized the east coast of North America, and France colonized the central region of North America. Russia made incursions onto the northwest coast of  North America, with a first colony in present-day Alaska in 1784, and the outpost of Fort Ross in present-day California in 1812. In 1762, in the midst of the Seven Years' War, France secretly ceded most of its North American claims to Spain in the Treaty of Fontainebleau. Thirteen of the British colonies declared independence as the United States of America in 1776, ratified by the Treaty of Paris in 1783, ending the American Revolutionary War. Napoleon Bonaparte won France's claims back from Spain in the Napoleonic Wars in 1800, but sold them to the United States  in 1803 as the Louisiana Purchase. Late modern period (1800 to the present). 19th century. The Scientific Revolution changed humanity's understanding of the world and led to the Industrial Revolution, a major transformation of the world's economies. The Scientific Revolution in the 17th century had had little immediate effect on industrial technology; only in the second half of the 18th century did scientific advances begin to be applied substantially to practical invention. The Industrial Revolution began in Great Britain and used new modes of production—the factory, mass production, and mechanization—to manufacture a wide array of goods  faster and using less labour than previously required. The Age of Enlightenment also led to the beginnings of modern democracy in the late-18th century American and French revolutions. Democracy and republicanism would grow to have a profound effect on world events and on quality of life. After Europeans had achieved influence and control over the Americas, imperial activities turned to the lands of Asia and Oceania. In the 19th century the European states had social and technological advantage over Eastern lands. Britain gained control of the Indian subcontinent, Egypt and the Malay Peninsula; the French took Indochina; while the Dutch  cemented their control over the Dutch East Indies. The British also colonized Australia, New Zealand and South Africa with large numbers of British colonists emigrating to these colonies. Russia colonized large pre-agricultural areas of Siberia. In the late 19th century, the European powers divided the remaining areas of Africa. Within Europe, economic and military challenges created a system of nation states, and ethno-linguistic groupings began to identify themselves as distinctive nations with aspirations for cultural and political autonomy. This nationalism would become important to peoples across the world in the 20th century. The advantages that Europe had developed  by the mid-18th century were two: an entrepreneurial culture, and the wealth generated by the Atlantic trade (including the African slave trade). The profits of the slave trade and of West Indian plantations amounted to 5% of the British economy at the time of the Industrial Revolution. While some historians conclude that, in 1750, labour productivity in the most developed regions of China was still on a par with that of Europe's Atlantic economy, other historians such as Angus Maddison hold that the per-capita productivity of western Europe had by the late Middle Ages surpassed that of all  other regions. During the Second Industrial Revolution, the world economy became reliant on coal as a fuel, as new methods of transport, such as railways and steamships, effectively shrank the world. Meanwhile, industrial pollution and environmental damage, present since the discovery of fire and the beginning of civilization, accelerated drastically. 20th century. The 20th century opened with Europe at an apex of wealth and power, and with much of the world under its direct colonial control or its indirect domination. Much of the rest of the world was influenced by heavily Europeanized nations: the United States and Japan. As the  century unfolded, however, the global system dominated by rival powers was subjected to severe strains, and ultimately yielded to a more fluid structure of independent nations organized on Western models. This transformation was catalyzed by wars of unparalleled scope and devastation. World War I led to the collapse of four empires – Austria-Hungary, the German Empire, the Ottoman Empire, and the Russian Empire – and weakened the United Kingdom and France. The Armenian, Syriac and Greek genocide were the systematic destruction, mass murder and expulsion of the Armenians, Assyrians and Greeks in the Ottoman Empire during World War I, spearheaded by  the ruling Committee of Union and Progress (CUP). In the war's aftermath, powerful ideologies rose to prominence. The Russian Revolution of 1917 created the first communist state, while the 1920s and 1930s saw militaristic fascist dictatorships gain control in Italy, Germany, Spain, and elsewhere. From 1918 to 1920, the Spanish flu caused the deaths of 17 to 100 million people. Ongoing national rivalries, exacerbated by the economic turmoil of the Great Depression, helped precipitate World War II. The militaristic dictatorships of Europe and Japan pursued an ultimately doomed course of imperialist expansionism, in the course of which Nazi Germany , under Adolf Hitler, orchestrated the genocide of six million Jews in the Holocaust, while Imperial Japan murdered millions of Chinese. The World War II defeat of the Axis powers by the Allied powers opened the way for the advance of communism into East Germany, Poland, Czechoslovakia, Hungary, Yugoslavia, Albania, Bulgaria, Romania, China, North Korea, and North Vietnam. When World War II ended in 1945, the United Nations was founded in the hope of preventing future wars, as the League of Nations had been formed following World War I. The war had left two countries, the United States and the Soviet  Union, with principal power to influence international affairs. Each was suspicious of the other and feared a global spread of the other's, respectively capitalist and communist, political-economic model. This led to the Cold War, a 45-year stand-off and arms race between the United States and its allies, on one hand, and the Soviet Union and its allies on the other. With the development of nuclear weapons during World War II, and with their subsequent proliferation, all of humanity were put at risk of nuclear war between the two superpowers, as demonstrated by many incidents, most prominently  the October 1962 Cuban Missile Crisis. Such war being viewed as impractical, the superpowers instead waged proxy wars in non-nuclear-armed Third World countries In China, Mao Zedong implemented industrialization and collectivization reforms as part of the Great Leap Forward (1958–1962), leading to the starvation deaths (1959–1961) of tens of millions of people. Between 1969 and 1972, as part of the Cold War Space Race, twelve American astronauts landed on the Moon and safely returned to Earth. The Cold War ended peacefully in 1991 after the Pan-European Picnic, the subsequent fall of the Iron Curtain and the Berlin  Wall, and the collapse of the Eastern Bloc and the Warsaw Pact. The Soviet Union collapsed, partly due to its inability to compete economically with the United States and Western Europe. The United States likewise began to show signs of slippage in its geopolitical influence, even as its private sector, now less inhibited by the claims of the public sector, increasingly sought private advantage to the prejudice of the public weal. In the early postwar decades, the colonies in Asia and Africa of the Belgian, British, Dutch, French, and other west European empires won their formal independence. However, these newly  independent countries often faced challenges in the form of neocolonialism, sociopolitical disarray, poverty, illiteracy, and endemic tropical diseases. Most Western European and Central European countries gradually formed a political and economic community, the European Union, which expanded eastward to include former Soviet satellite states. The European Union's effectiveness was handicapped by the immaturity of its common economic and political institutions, somewhat comparable to the inadequacy of United States institutions under the Articles of Confederation prior to the adoption of the Constitution of the United States that came into force in 1789. Asian, African, and South American countries followed suit  and began taking tentative steps toward forming their own respective continental associations. Cold War preparations to deter or to fight a third world war accelerated advances in technologies that, though conceptualized before World War II, had been implemented for that war's exigencies, such as jet aircraft, rocketry, and computers. In the decades after World War II, these advances led to jet travel, artificial satellites with innumerable applications including GPS and the Internet. These inventions have revolutionized the movement of people, ideas, and information. However, not all scientific and technological advances in the second half of the 20th century required  an initial military impetus. That period also saw ground-breaking developments such as the discovery of the structure of DNA and DNA sequencing, the consequent sequencing of the human genome (The Human Genome Project), the worldwide eradication of smallpox, the discovery of stem cells, the introduction of the portable cellular phone, the discovery of plate tectonics, crewed and uncrewed exploration of space and of previously inaccessible parts of Earth, and foundational discoveries in physics phenomena ranging from the smallest entities (particle physics) to the greatest entity (physical cosmology). In the 1990s, the Internet began to gain traction as a form  of communication. 21st century. The 21st century has been marked by growing economic globalization and integration, with consequent increased risk to interlinked economies, as exemplified by the Great Recession of the late 2000s and early 2010s. This period has also seen the expansion of communications with mobile phones and the Internet, which have caused fundamental societal changes in business, politics, and individuals' personal lives. Worldwide competition for natural resources has risen due to growing populations and industrialization, especially in India, China, and Brazil. The increased demands are contributing to increased environmental degradation and to climate change. In 2020, the COVID-19  pandemic substantially disrupted global trading and caused recessions in the global economy. As of 2022, more than six million people have died from COVID-19. In 2022, Russia launched a military invasion of Ukraine. The invasion caused Europe's largest refugee crisis since World War II, with more than five million Ukrainians leaving the country.