World War I

World War I (abbreviated WWI), also known as the First World War, the Great War and "The War to End All Wars" was a global military conflict that took place mostly in Europe between 1914 and 1918. It was a total war which left millions dead and helped to shape the modern world.
The Allied Powers, led by France, Russia, the British Empire, and later Italy and the United States, defeated the Central Powers: Austria-Hungary, the German Empire, Bulgaria and the Ottoman Empire.
Much of the fighting in World War I took place along the Western Front, within a system of opposing manned trenches and fortifications (separated by an empty space between the trenches called the "no man's land") running from the North Sea to the border of Switzerland. On the Eastern Front, the vast eastern plains and limited rail network prevented a trench warfare stalemate from developing, although the scale of the conflict was just as large. Hostilities also occurred on and under the sea and — for the first time — from the air. More than nine million soldiers died on the various battlefields, and millions more civilians perished.
The war caused the disintegration of four empires: the Austro-Hungarian, German, Ottoman, and Russian. Germany lost its overseas empire, and new states such as Czechoslovakia, Yugoslavia, Latvia, Lithuania and Estonia were created, or in the case of Poland, recreated.
World War I created a decisive break with the old world order that had emerged after the Napoleonic Wars, which was modified by the mid-19th century’s nationalistic revolutions. The outcomes of World War I would be important factors in the development of World War II 21 years later.
==Causes==
On June 28 1914, Gavrilo Princip shot and killed Archduke Franz Ferdinand, the heir to the Austrian throne, and his wife, in Sarajevo. Princip was a member of Young Bosnia, a group whose aims included the unification of the South Slavs and independence from Austria-Hungary (see also: the Black Hand). The assassination in Sarajevo set into motion a series of fast-moving events that escalated into a full-scale war. However, the ultimate causes of the conflict were multiple and complex.
===Arms races===
The naval arms race that developed between Britain and Germany was intensified by the 1906 launch of HMS Dreadnought, a revolutionary warship that rendered all previous battleships obsolete. (Britain maintained a large lead over Germany in all categories of warship.) Paul Kennedy has pointed out that both nations believed in Alfred Thayer Mahan's thesis that command of the sea was vital to a great nation. 
David Stevenson described the armaments race as "a self-reinforcing cycle of heightened military preparedness", while David Herrman viewed the shipbuilding rivalry as part of a general movement towards war. However, Niall Ferguson argues that Britain’s ability to maintain an overall advantage signifies that change within this realm was insignificant and therefore not a factor in the movement towards war.
The naval strength of the powers in 1914	The naval strength of the powers in 1914	The naval strength of the powers in 1914	The naval strength of the powers in 1914
Country 	Personnel 	Large
Naval
Vessels 	Tonnage
Russia 	54,000 	4 	328,000
France 	68,000 	10 	731,000
Britain 	209,000 	29 	2,205,000
TOTAL 	331,000 	43 	3,264,000
Germany 	79,000 	17 	1,019,000
Austria-Hungary 	16,000 	3 	249,000
TOTAL 	95,000 	20 	1,268,000
Source: Ferguson 1999 p 85 	Source: Ferguson 1999 p 85 	Source: Ferguson 1999 p 85 	Source: Ferguson 1999 p 85
===Plans, distrust and mobilization===
Closely related is the thesis adopted by many political scientists that the war plans of Germany, France and Russia automatically escalated the conflict. Fritz Fischer and his followers have emphasized the inherently aggressive nature of the Schlieffen Plan, which outlined German strategy if at war with both France and Russia. Conflict on two fronts meant Germany had to eliminate one opponent quickly before taking on the other, relying on a strict timetable. It called for a strong right flank attack, to seize Belgium and cripple the French army by preempting its mobilization.
After the attack, the German army would then rush to the eastern front by railroad and quickly destroy the more slowly mobilizing military of Russia.
In a greater context, France's own Plan XVII called for an offensive thrust into Germany’s industrial Ruhr Valley which would cripple Germany’s ability to wage war.
Russia’s revised Plan XIX implied a mobilization of its armies against both Austria-Hungary and Germany. 
All three created an atmosphere where generals and planning staffs were anxious to take the initiative and seize decisive victories. Elaborate mobilization plans with precise timetables had been prepared. Once the mobilization orders were issued, it was understood by both generals and statesmen alike that there was little or no possibility of turning back or a key advantage would be sacrificed. Furthermore, the problem of communications in 1914 should not be underestimated; all nations still used telegraphy and ambassadors as the main form of communication, which resulted in delays from hours to even days.
===Militarism and autocracy===
President of the United States Woodrow Wilson and other observers blamed the war on militarism. October 30, 1918 in Herbert Hoover, Ordeal of Woodrow Wilson p. 47 The idea was that aristocrats and military elites had too much control over Germany, Russia and Austria, and the war was a consequence of their desire for military power and disdain for democracy. This was a theme that figured prominently in anti-German propaganda, which cast Kaiser Wilhelm II and Prussian military tradition in a negative light. Consequently, supporters of this theory called for the abdication of such rulers, the end of the aristocratic system and the end of militarism — all of which justified American entry into the war once Czarist Russia dropped out of the Allied camp.
Wilson hoped the League of Nations and universal disarmament would secure a lasting peace. He also acknowledged variations of militarism that, in his opinion, existed within the British and French political systems.
===Economic imperialism===
Vladimir Lenin asserted that the worldwide system of imperialism was responsible for the war. In this, he drew upon the economic theories of Karl Marx and English economist John A. Hobson, who had earlier predicted the outcome of economic imperialism, or unlimited competition for expanding markets, would lead to a global military conflict.“Imperialism" (1902)fordham.edu website This argument proved popular in the immediate wake of the war and assisted in the rise of Marxism and Communism. Lenin argued that large banking interests in the various capitalist-imperialist powers had pulled the strings in the various governments and led them into the war.1917 pamphlet “Imperialism: The Highest Stage of Capitalism”
===Trade barriers===
Cordell Hull believed that trade barriers were the root cause of both World War I and World War II, and designed the Bretton Woods Agreements to reduce trade barriers, and thus eliminate what he saw as the root cause of the two world wars.
International bond and financial markets entered severe crises in late July and early August; this reflected worry about the financial consequences of war.
===Culmination of European history===
A localized war between Austria-Hungary and Serbia was considered inevitable due to Austria-Hungary’s deteriorating world position and the Pan-Slavic separatist movement in the Balkans. The expansion of such ethnic sentiments coincided with the growth of Serbia and the decline of the Ottoman Empire, as the latter had formerly held sway over much of the region. Imperial Russia also supported the Pan-Slavic movement, motivated by ethnic loyalties, dissatisfaction with Austria (dating back to the Crimean War) and a century-old dream of a warm water port.Web reference For Germany, their location in the center of Europe led to the decision for an active defense, culminating in the Schlieffen Plan.At the same time, the transfer of the contested and Lorraine territories and defeat in the Franco-Prussian War influenced France’s policy, characterized by . The French formed an alliance with Russia and a two-front war became a distinct possibility for Germany.
==Opposition to the war ==
The trade union and socialist movements had declared before the war their determined opposition to a war which they said could only mean workers killing each other in the millions in the interests of their capitalist employers. Once the war was declared, however, the vast majority of socialist and trade union bodies decided to back the government of their respective countries and support the war. The few exceptions were the Russian Bolsheviks, the Italian Socialist Party, Karl Liebknecht, Rosa Luxemburg and their followers in Germany, and very small groups in Britain and France. Other opposition came from conscientious objectors - some socialist, some religious - who refused to fight in the war.
==July crisis and declarations of war==
After the assassination of June 28, Austria-Hungary waited for 3 weeks before deciding on a course of action, obtaining first a "blank check" from Germany that promised support for whatever it decided. The Austro-Hungarian government, once assured of support, moved to crush Serbia. On July 23 Austro-Hungary issued the July Ultimatum to Serbia, demanding among other things that Austrian agents be allowed to take part in the investigation of the assassination, and that Serbia should take responsibility for it.Strachen (2001) 1:75-81, 88 
The Serbian government accepted all the terms of the ultimatum, with the exception of those relating to the participation of the Austrian agents in the inquiry, which Serbia regarded as a violation of its sovereignty. Breaking diplomatic relations, Austria Hungary declared war on Serbia on July 28 and proceeded to bombard Belgrade with artillery on July 29. On July 30, both Austria-Hungary and Russia ordered general mobilizations of their armies.
Having pledged its support to Austria-Hungary, Germany issued Russia an ultimatum on July 31, demanding a halt to mobilization within 12 hours. On August 1, with the ultimatum expired, the German ambassador to Russia formally declared war. 
On August 2, Germany occupied Luxembourg, as a preliminary step to the invasion of Belgium and implementation of the Schlieffen Plan (which was rapidly going awry, as the Germans had not intended to be at war with a mobilised Russia this quickly). 
Yet another ultimatum was delivered to Belgium on August 2, requesting free passage for the German army on the way to France. The Belgians refused. At the very last moment, the Kaiser Wilhelm II asked Moltke, the German Chief of General Staff, to cancel the invasion of France in the hope this would keep Britain out of the war. Moltke refused on the grounds that it would be impossible to change the rail schedule—“once settled, it cannot be altered”.Moltke quoted in Tuchman’s The Guns of August, page xxx The question of whether such a radical change in Germany’s plans would have indeed been possible has been the subject of much dispute. When Moltke’s reply was revealed after the war to General von Staab, Germany’s Chief of the Railway Division, he saw it as an affront to the capabilities of his unit, and proceeded to write a book proving such a change was indeed possible. General von Staab quoted in Tuchman, The Guns of August, p464; Matthias Erzberger, the Reichstag deputy, later testified that six months after the outbreak of war, Moltke admitted that attacking France first was a mistake and that “the larger part of our army ought first to have been sent to the East to smash the Russian steamroller” Quoted in Tuchman The Guns of August, p464
On August 3, Germany declared war on France and invaded Belgium on August 4. This act violated Belgian neutrality, to which status Germany, France, and Britain were all committed by treaty. It was inconceivable that Great Britain would remain neutral if Germany declared war on France; German violation of Belgian neutrality provided the casus belli that the British government sought. German Chancellor Bethmann Hollweg told the Reichstag that the German invasions of Belgium and Luxemburg was in violation of international law, but argued that Germany was "in a state of necessity, and necessity knows no law." Later that same day, in a conversation with the British ambassador Sir Edward Goschen, Bethmann expressed astonishment that the British would go to war with Germany over the 1839 treaty guaranteeing the neutrality of Belgium, referring to the treaty dismissively as a "scrap of paper," a statement that outraged public opinion in Britain and the United States.Sally Marks, The Ebbing of European Ascendancy: An International History of the World 1914-1945 (2002) p. 30; Francis Anthony Boyle, Foundations of World Order: The Legalist Approach to International Relations (1898-1922) Duke University Press, 1999, p 134; Tuchman, The Guns of August, page 153. Britain's guarantee to Belgium prompted Britain, which had been neutral, to declare war on Germany on August 4. The British government expected a limited war, in which it would primarily use its great naval strength.Strachen, The First World War (2001) 1:97-98
== Opening hostilities ==
=== Europe ===
In Europe, the Central Powers—the German Empire and the Austro-Hungarian Empire—suffered from mutual miscommunication and lack of intelligence regarding the intentions of each other’s army. Germany had originally guaranteed to support Austria-Hungary’s invasion of Serbia but practical interpretation of this idea differed. Austro-Hungarian leaders believed Germany would cover the northern flank against Russia. Germany, however, had planned for Austria-Hungary to focus the majority of its troops on Russia while Germany dealt with France on the Western Front. This confusion forced the Austro-Hungarian army to split its troop concentrations. Somewhat more than half of the army went to fight the Russians on their border, and the remainder was allocated to invade and conquer Serbia.
=== Serbian Campaign ===
 
The Serbian army fought a defensive battle against the invading Austrian army (called the Battle of Cer) starting on August 12. The Serbians occupied defensive positions on the south side of the Drina and Sava rivers. Over the next two weeks Austrian attacks were thrown back with heavy losses. This marked the first major Allied victory of the war. Austrian expectations of a swift victory over Serbia were not realized and as a result, Austria had to keep a very sizable force on the Serbian front, which weakened their armies facing Russia.
=== German forces in Belgium and France ===
Initially, the Germans had great successes in the Battle of the Frontiers (August 14–August 24). However, Russia attacked in East Prussia and diverted German forces intended for the Western Front. Germany defeated Russia in a series of battles collectively known as the Second Battle of Tannenberg (August 17–September 2). This diversion exacerbated problems of insufficient speed of advance from railheads not allowed for by the German General Staff. Originally, the Schlieffen Plan called for the right flank of the German advance to pass to the west of Paris. However, the capacity and low speed of horse-drawn transport hampered the German supply train, allowing French and British forces to finally halt the German advance east of Paris at the First Battle of the Marne (September 5–12), thereby denying the Central Powers a quick victory over France and forcing them to fight a war on two fronts. The German army had fought its way into a good defensive position inside France and had permanently incapacitated 230,000 more French and British troops than it had lost itself in the months of August and September. Yet communications problems and questionable command decisions (such as Moltke transferring troops from the right to protect Sedan) cost Germany the chance for an early victory over France with its very ambitious war plan.
=== Africa and Pacific ===
In August 1914, French and British Empire forces invaded the German protectorate of Togoland in West Africa. Shortly thereafter, on August 10, German forces based in South-West Africa attacked South Africa. An Anglo-Indian army was raised, which landed in Basra in November 1914. New Zealand occupied German Samoa (later Western Samoa) on August 30. On September 11, the Australian Naval and Military Expeditionary Force landed on the island of Neu Pommern (later New Britain), which formed part of German New Guinea. Japan seized Germany’s Micronesian colonies and the German coaling port of Qingdao, in the Chinese Shandong peninsula. Within a few months, the Allied forces had seized all the German territories in the Pacific. However, sporadic and fierce fighting continued in East Africa for the remainder of the war, as German forces recruited native soldiers and evaded capture.
==Early stages==
===Trench warfare begins===
Military tactics in the early part of World War I failed to keep pace with advances in military technology. These new technologies allowed the construction of formidable static defenses, which obsolete attack strategies could not penetrate. Barbed wire was a significant hindrance to massed infantry advances; artillery, now vastly more lethal than in the 1870s, coupled with machine guns, made crossing open ground a nightmarish prospect. Germans introduced poison gas in 1915, at the first battle of Ypres, which soon became a weapon used by both sides. Poisonous gas never won a battle; however, its effects were brutally horrific, causing slow and painfully greusome deaths which made life even more miserable in the trenches. It became one of the most feared and longest remembered horrors of the war. Tacticians on both sides failed to develop tactics capable of breaking through entrenched positions without massive casualties until technology began to yield new offensive weapons. The war saw the invention of tanks as another attempt to break the trench warfare stalemate. They were primarily used by the British and French, though the Germans used captured Allied tanks and a small number of their own design.
After the First Battle of the Marne, both Entente and German forces began a series of outflanking maneuvers to try to force the other to retreat, in the so-called Race to the Sea. Britain and France soon found themselves facing entrenched German positions from Lorraine to Belgium’s Flemish coast. Britain and France sought to take the offensive, while Germany defended occupied territories. One consequence was that German trenches were much better constructed than those of their enemy: Anglo-French trenches were only intended to be “temporary” before their forces broke through German defenses. Some hoped to break the stalemate by utilizing science and technology. In April 1915, the Germans used chlorine gas, for the first time, which opened a 6 kilometer (4 mi) wide hole in the Allied lines when French colonial troops retreated before it. This breach was closed by allied soldiers at the Second Battle of Ypres (where over 5,000 mainly Canadian soldiers were gassed to death) and Third Battle of Ypres, where Canadian forces took the village of Passchendaele.
On July 1, 1916, the first day of the Battle of the Somme, the British Army saw the bloodiest day in its history, suffering 57,470 casualties and 19,240 dead. 
Neither side proved able to deliver a decisive blow for the next two years, though protracted German action at Verdun throughout 1916, and the Entente’s failure at the Somme, in the summer of 1916, brought the exhausted French army to the brink of collapse. Futile attempts at frontal assault—with a rigid adherence to unimaginative maneuver—came at a high price for both the British and the French poilu (infantry) and led to widespread mutinies especially during the time of the Nivelle Offensive in the spring of 1917. News of the Russian Revolution gave a new incentive to socialist sentiments among the troops, with its seemingly inherent promise of peace. Red flags were hoisted, and the Internationale was sung on several occasions. At the height of the mutiny, 30,000 to 40,000 French soldiers participated.
Throughout 1915–17, the British Empire and France suffered far more casualties than Germany. However, while the Germans only mounted a single main offensive at Verdun, each failed attempt by the Entente to break through German lines was met with an equally fierce German counteroffensive to recapture lost positions. Around 800,000 soldiers from the British Empire were on the Western Front at any one time. 1,000 battalions, each occupying a sector of the line from the North Sea to the Orne River, operated on a month-long four-stage rotation system, unless an offensive was underway. The front contained over 9,600 kilometers (6,000 mi) of trenches. Each battalion held its sector for about a week before moving back to support lines and then further back to the reserve lines before a week out-of-line, often in the Poperinge or Amiens areas.
In the British-led Battle of Arras during the 1917 campaign, the only military success was the capture of Vimy Ridge by the Canadian forces under Sir Arthur Currie and Julian Byng. It provided the British allies with great military advantage that had a lasting impact on the war and is considered by many historians as the founding myth of Canada.
==Naval War==
Main article: Naval Warfare in World War I
At the start of the war, the German Empire had cruisers scattered across the globe that they subsequently used to attack Allied merchant shipping. The British Royal Navy thereafter systematically hunted them down: at the Battle of the Falkland Islands in December 1914, for example, Germany lost a fleet of 2 armoured cruisers, 2 light cruisers, and 2 transports. 
Soon after the war began, Britain initiated a Naval Blockade of Germany, preventing supply ships from reaching German ports. This strategy proved extremely effective, cutting off vital supplies from the German army and devastating Germany's economy in the homefront, leading to mass famine and starvation across the country. Furthermore, due to Britain's control of the sea, they were able to carry out their blockade often without firing a shot by simply boarding the ships, confiscating their cargo, and then letting the ship go afterwards. This strategy minimized casualties from ships belonging to nations not involved in the war. As a result, none of the neutral nations ever made a serious demand to end the blockade.
The 1916 Battle of Jutland (German: Skagerrakschlacht, or "Battle of the Skagerrak") developed into the largest naval battle of the war, and - remarkably - the only full-scale clash of battleships between the two sides. The Battle of Jutland was fought on May 31–June 1, 1916, in the North Sea off Jutland, the mainland of Denmark. The combatants were the Kaiserliche Marine's High Seas Fleet commanded by Vice Admiral Reinhard Scheer and the Royal Navy's Grand Fleet commanded by Admiral Sir John Jellicoe. The battle was a standoff as the Germans, outmaneuvered by the larger British fleet, managed to escape to base. Strategically, the British demonstrated their control of the seas, and the German navy thereafter remained largely confined to port, where disgruntled sailors eventually mutinied in October 1918.
German U-boats threatened to cut the supply lines between North America and Britain. Due to the need to maintain positional secrecy, attacks came without warning, giving the crews of the targeted ships little chance to escape. The United States protested, and Germany modified its rules of engagement and - after the infamous sinking of the passenger ship RMS Lusitania in 1915 - it promised not to sink passenger liners. Britain armed its merchant ships. Finally, in early 1917 Germany decided on a policy of unrestricted submarine warfare, realising the Americans would enter the war. Germany gambled that it would be able to strangle the Allied supply line before the Americans could train and transport a large army. 
The U-boat threat was solved in 1917 by herding merchants ships into convoys escorted by destroyers. This tactic made it much harder for U-boats to find targets, and the destroyers made it likely the slower submarines would be sunk by a highly effective new weapon, the depth charge. The losses to submarine attacks became quite small, but the convoy system slowed the flow of supplies, because the convoy travelled at the speed of the slowest ship, and ships had to wait to be assembled and wait again to be unloaded. The solution to the delays was a massive program of building new freighters. Troop ships were too fast for the submarines and did not travel the North Atlantic in convoys.
The First World War also saw the first use of aircraft carriers in combat, with HMS Furious launching Sopwith Camels in a successful raid against the Zeppelin hangars at Tondern in July 1918.
==Southern theatres==
===Ottoman Empire===
 
The Ottoman Empire joined the Central Powers in October and November 1914, because of the secret Ottoman-German Alliance, by three Pashas, which was signed in August 1914. It threatened Russia’s Caucasian territories and Britain’s communications with India and the East via the Suez canal. The British and French opened another front in the South with the Gallipoli (1915) and Mesopotamian campaigns. In Gallipoli, the Turks were successful in repelling the British, French, and Australian and New Zealand Army Corps (ANZACs) and forced their eventual withdrawal and evacuation. In Mesopotamia, by contrast, after the disastrous Siege of Kut (1915–16), British Empire forces reorganized and captured Baghdad in March 1917. Further to the west in the Sinai and Palestine Campaign, initial British failures were overcome when Jerusalem was captured in December 1917, and the Egyptian Expeditionary Force, under Field Marshal Edmund Allenby, broke the Ottoman forces at the Battle of Megiddo in September 1918.
Russian armies generally had the best of it in the Caucasus.
Vice-Generalissimo Enver Pasha, supreme commander of the Turkish armed forces, was a very ambitious man with a dream to conquer central Asia. He was not, however, a practical soldier. He launched an offensive with 100,000 troops against the Russians in the Caucasus in December of 1914. Insisting on a frontal attack against Russian positions in the mountains in the heart of winter, Enver lost 86% of his force at the Battle of Sarikamis. 
The Russian commander from 1915 to 1916, General Yudenich, with a string of victories over the Ottoman forces, drove the Turks out of much of the southern Caucasus. 
In 1917, Russian Grand Duke Nicholas assumed senior control over the Caucasus front. Nicholas tried to have a railway built from Russian Georgia to the conquered territories with a view to bringing up more supplies for a new offensive in 1917. But, in March of 1917 (February in the pre-revolutionary Russian calendar), the Czar was overthrown in the February Revolution and the Russian army began to slowly fall apart.
===Italian participation===
Italy had been allied to the German and Austro-Hungarian Empires since 1882. However, Italy had its own designs against Austrian territory in the Trentino, Istria and Dalmatia, and maintained a secret 1902 understanding with France, which effectively nullified its alliance commitments. Italy refused to join Germany and Austria-Hungary at the beginning of the war because their alliance (the "Triple Alliance") was defensive, while Austria-Hungary was the attacker. The Austrian government started negotiations to obtain Italian neutrality in exchange for French territories (Tunisia), but Italy joined the Entente by signing the London Pact in April and declaring war on Austria-Hungary in May 1915; it declared war against Germany fifteen months later.
In general, the Italians had numerical superiority but this advantage was squandered (along with the later increase in the size and quality of artillery which by 1917 rivalled the British and French gun parks) by the obstinacy with which Italian Generalissimo Luigi Cadorna insisted on attacking the Isonzo Front. Cadorna, a staunch proponent of the frontal assault, had dreams of breaking into the Slovenian plateau, taking Ljubljana and then threatening Vienna itself; it was a Napoleonic plan which had no realistic chance in the age of barbed wire and machine guns. Cadorna unleashed 11 offensives (Isonzo Battles) with total disregard for his men's lives. The Italians went on the offensive to relieve pressure on the other Allied fronts and achieve their territorial goals. In the Trentino front, the Austro-Hungarian defense took advantage of the elevation of their bases in the mostly mountainous terrain, which was not suitable for military offensives. After an initial Austro-Hungaric strategic retreat to better positions, the front remained mostly unchanged, while Austrian Kaiserschützen and Standschützen and Italian Alpini fought bitter close combat battles during summer and tried to survive during winter in the high mountains. The Austro-Hungarians counterattacked in the Altopiano of Asiago towards Verona and Padua in the spring of 1916 (Strafexpedition), but they also made little progress.
Beginning in 1915, the Italians mounted 11 major offensives along the Isonzo River north of Trieste, known collectively as the Battle of the Isonzo. These eleven battles were repelled by the Austro-Hungarians who had the higher ground. In the summer of 1916, the Italians captured the town of Gorizia. After this minor victory, the front remained practically stable for over a year, despite several Italian offensives. In the fall of 1917, thanks to the improving situation on the Eastern front, the Austrians received large reinforcements, including German assault troops. The Central Powers launched a crushing offensive on October 26 that was spearheaded by German troops and supported by the Austrians and Hungarians. The attack resulted in the victory at Caporetto: the Italian army was routed, but after retreating more than 100 km, it was able to reorganise and hold at the Piave River. In 1918, the Austrians repeatedly failed to break the Italian line in battles such as the battle on the Asiago Plateau and, decisively defeated in the Battle of Vittorio Veneto, surrendered to the Entente powers in November.
===War in the Balkans===
Faced with the Russian threat, Austria-Hungary could spare only one third of its army for Serbia. After suffering tremendous losses, the Austrians briefly captured the Serbian capital, but Serb counterattacks succeeded in expelling the invaders from the country by the end of 1914. For the first 10 months of 1915, Austria used most of its spare armies to fight Italy. However, German and Austrian diplomats scored a great coup by convincing Bulgaria to join in a new attack on Serbia.
The conquest of Serbia was finally accomplished in a little more than a month, starting on October 7, when the Austrians and Germans attacked from the north. Four days later the Bulgarians attacked from the east. The Serbian army, attacked from two directions and facing certain defeat, retreated east and south into Albania, stopping only once to make a stand against the Bulgarians, near modern day Gjilan, Kosovo, where they again suffered defeat. From Albania they went by ship to Greece.
In late 1915, a Franco-British force landed at Salonica in Greece to offer assistance and to pressure the Greek government into war against the Central Powers. Unfortunately for the Allies, the pro-Allied Greek government of Eleftherios Venizelos was dismissed, by the pro-German King Constantine I, before the allied expeditionary force had even arrived. 
The Salonica Front proved entirely immobile, so much so that it was joked that Salonica was the largest German prisoner of war camp. Only at the very end of the war were the Entente powers able to make a breakthrough, which was after most of the German and Austro-Hungarian troops had been removed, leaving the Front held by the Bulgarians alone. This led to Bulgaria’s signing an armistice on September 29, 1918.
==Eastern Front==
===Initial actions===
While the Western Front had reached stalemate in the trenches, the war continued in the east. The Russian initial plans for war had called for simultaneous invasions of Austrian Galicia and German East Prussia. Although Russia’s initial advance into Galicia was largely successful, they were driven back from East Prussia by the victories of the German generals Hindenburg and Ludendorff at Tannenberg and the Masurian Lakes in August and September 1914. Russia’s less developed industrial base and ineffective military leadership was instrumental in the events that unfolded. By the spring of 1915, the Russians were driven back in Galicia, and in May, the Central Powers achieved a remarkable breakthrough on Poland’s southern fringes, capturing Warsaw on August 5 and forcing the Russians to withdraw from all of Poland. This became known as the “Great Retreat” by the Russian Empire and the “Great Advance” by Germany.
===Russian Revolution===
Dissatisfaction with the Russian government’s conduct of the war grew despite the success of the June 1916 Brusilov offensive in eastern Galicia against the Austrians. The Russian success was undermined by the reluctance of other generals to commit their forces in support of the victorious sector commander. Allied and Russian forces revived only temporarily with Romania’s entry into the war on August 27: German forces came to the aid of embattled Austrian units in Transylvania, and Bucharest fell to the Central Powers on December 6. Meanwhile, internal unrest grew in Russia as the Tsar remained out of touch at the front. Empress Alexandra’s increasingly incompetent rule drew protests from all segments of Russian political life and resulted in the murder of Alexandra’s favorite Rasputin by conservative noblemen at the end of 1916.
thumb|left|180px|Vladimir Lenin
In March 1917, demonstrations in St. Petersburg culminated in the abdication of Tsar Nicholas II and the appointment of a weak Provisional Government, which shared power with the socialists of the Petrograd Soviet. This division of power led to confusion and chaos both on the front and at home, and the army became increasingly ineffective.
The war, and the government, became more and more unpopular, and the discontent led to a rise in popularity of the Bolshevik party, led by Vladimir Lenin, who promised pulling Russia out of the war and were able to gain power. The triumph of the Bolsheviks in November was followed in December by an armistice and negotiations with Germany. At first, the Bolsheviks refused to agree to the harsh German terms, but when Germany resumed the war and marched with impunity across Ukraine, the new government acceded to the Treaty of Brest-Litovsk on March 3, 1918, which took Russia out of the war and ceded vast territories, including Finland, the Baltic provinces, parts of Poland and Ukraine to the Central Powers.
The publication by the new Bolshevik government of the secret treaties signed by the tsar was hailed across the world either as a great step forward for the respect of the will of the people, or as a dreadful catastrophe which could destabilize the world. The existence of a new type of government in Russia led to the reinforcement in many countries of Communist parties. 
After the Russians dropped out of the war, the Entente no longer existed. The Allied powers led a small-scale invasion of Russia. The invasion was made with intent primarily to stop Germany from exploiting Russian resources and, to a lesser extent, to support the Whites in the Russian Revolution. Troops landed in Archangel (see North Russia Campaign) and in Vladivostok.
==1917–18==
Events of 1917 would prove decisive in ending the war, although their effects would not be fully felt until 1918. The British naval blockade of Germany began to have a serious impact on morale and productivity on the German home front. In response, in February 1917, the German General Staff (OHL) was able to convince Chancellor Theobald von Bethmann-Hollweg to declare unrestricted submarine warfare with the goal of starving Britain out of the war. Tonnage sunk rose above 500,000 tons per month from February until July, peaking at 860,000 tons in April. After July, the reintroduced convoy system was extremely effective in neutralizing the U-boat threat. Britain was safe from the threat of starvation, and the German war industry remained deprived materially. 
The decisive victory of Austria-Hungary and Germany at the Battle of Caporetto led to the Allied decision at the Rapallo Conference to form the Supreme Allied Council at Versailles to coordinate plans and action. Previously British and French armies had operated under separate command systems.
In December, the Central Powers signed an armistice with Russia, thereby releasing troops from the eastern front for use in the west. Ironically, German troop transfers could have been greater if their territorial acquisitions had not been so dramatic. With both German reinforcements and new American troops pouring into the Western Front, the final outcome of the war was to be decided in that front. The Central Powers knew that they could not win a protracted war now that American forces were certain to be arriving in increasing numbers, but they held high hopes for a rapid offensive in the West. Using freshly rested troops to reinforced, mainly Australian and Canadian shock troops, and new infantry tactics devised by Australian Sir General Monash, led the Allies to Victory. Furthermore, the rulers of both the Central Powers and the Allies became more fearful of the threat first raised by Ivan Bloch in 1899, that protracted industrialized war threatened social collapse and revolution throughout Europe. Both sides urgently sought a decisive, rapid victory on the Western Front because they were both fearful of collapse or stalemate.
===Entry of the United States===
America’s policy of insisting on neutral rights while also trying to broker a peace resulted in tensions with both Berlin and London. When a German U-boat sank the Lusitania in 1915, a large passenger liner with 128 Americans aboard, Wilson vowed "America was too proud to fight," and demanded an end to attacks on passenger ships. Germany complied. Wilson tried to mediate a compromise settlement; yet no compromise was discovered. Wilson also repeatedly warned that America would not tolerate unrestricted submarine warfare because it violated America's rights. Wilson was under great pressure from former president Teddy Roosevelt, who denounced German "piracy" and Wilson's cowardice. In January 1917 the Germans announced they would resume unrestricted submarine warfare. Berlin's proposal to Mexico to join the war as Germany's ally against the U.S. was exposed in February, angering American opinion. (see Zimmermann Telegram). After German submarines attacked several American merchant ships, sinking three, Wilson requested that Congress declare war on Germany, which it did on April 6, 1917.(see: Woodrow Wilson declares war on Germany on ). The U.S. House of Representatives approved the war resolution 373-50, the U.S. Senate 82-6, with opposition coming especially from German American districts such as Wisconsin. The U.S. declared war on Austria-Hungary in December 1917.
The United States was never formally a member of the Allies but an “Associated Power”. Significant numbers of fresh American troops arrived in Europe in the summer of 1918, and they started arriving at 10,000 per day. Germany miscalculated that it would be many more months before large numbers of American troops could be sent to Europe, and that, in any event, the U-boat offensive would prevent their arrival. In fact, not a single American infantryman lost his life due to German U-boat activity.
The United States Navy sent a battleship group to Scapa Flow to join with the British Grand Fleet, several destroyers to Queenstown, Ireland, and several submarines to the Azores and to Bantry Bay, Ireland, to help guard convoys. Several regiments of U.S. Marines were also dispatched to France. However, it would be some time before the United States would be able to contribute significant personnel to the Western and Italian fronts.
The British and French wanted the United States to send its infantry to reinforce their troops already on the battlelines, and not use scarce shipping to bring over supplies. Thus the Americans primarily used British and French artillery, aircraft and tanks. However, General John J. Pershing, American Expeditionary Force (AEF) commander, refused to break up American units to be used as reinforcements for British Empire and French units (though he did allow African American combat units to be used by the French). Pershing ordered the use of frontal assaults, which had been discarded by that time by British Empire and French commanders because of the large loss of life sustained throughout the war.
===German Spring Offensive of 1918===
German General Erich Ludendorff drew up plans (codenamed Operation Michael) for a 1918 general offensive along the Western Front. This Spring Offensive sought to divide the British and French armies in a series of feints and advances. The German leadership hoped to strike a decisive blow against the enemy before significant United States forces could be deployed.
Operation Michael opened on March 21, 1918, with an attack against British forces near the rail junction at Amiens. Ludendorff’s intention was to split the British and French armies at this point. German forces achieved an unprecedented advance of 60 kilometers (40 mi). For the first time since 1914, maneuvering was achieved on the battlefield.
British and French trenches were defeated using novel infiltration tactics, also called Hutier tactics after General Oskar von Hutier. Up to this time, attacks had been characterized by long artillery bombardments and continuous-front mass assaults. However, in the Spring Offensive, the German Army used artillery briefly and infiltrated small groups of infantry at weak points, attacking command and logistics areas and surrounding points of serious resistance. These isolated positions were then destroyed by more heavily armed infantry. German success relied greatly on this tactic.
The front line had now moved to within 120 kilometers (75 mi) of Paris. Three super-heavy Krupp railway guns advanced and fired 183 shells on Paris, which caused many Parisians to flee the city. The initial stages of the offensive were so successful that German Kaiser Wilhelm II declared March 24 a national holiday. Many Germans thought victory was close; however, after heavy fighting, the German offensive was halted. Infiltration tactics had worked very well, but the Germans, lacking tanks or motorized artillery, were unable to consolidate their positions. The British and French learned that if they fell back a few miles, the Germans would be disorganized and vulnerable to counterattack.
American divisions, which Pershing had sought to field as an independent force, were assigned to the depleted French and British Empire commands on March 28. A supreme command of Allied forces was created at the Doullens Conference, in which British Field Marshal Douglas Haig handed control of his forces over to Ferdinand Foch.
Following Operation Michael, Germany launched Operation Georgette to the north against the Channel ports. This was halted by the Allies with less significant territorial gains to Germany. Operations Blücher and Yorck were then conducted by the German Army to the south, broadly towards Paris. Next, Operation Marne was launched on July 15 as an attempt to encircle Reims, beginning the Second Battle of the Marne. The resulting Allied counterattack marked their first successful offensive of the war. By July 20, the Germans were back at their Kaiserschlacht starting lines, having achieved nothing. Following this last phase of the ground war in the West, the German Army never again held the initiative. German casualties between March and April 1918 were 270,000, including many of the highly trained stormtroopers. Their best soldiers were gone just as the Americans started arriving.
Meanwhile, Germany was crumbling internally as well. Anti-war marches were a frequent occurrence and morale within the army was at low levels. Industrial output had fallen 53% from 1913.
===Allied victory: summer and autumn 1918===
The Allied counteroffensive, known as the Hundred Days Offensive began on August 8, 1918. The Battle of Amiens developed with III Corps Fourth British Army on the left, the First French Army on the right, and the Australian Corps and Canadians spearheading the offensive in the centre. It involved 414 tanks of the Mark IV and Mark V type, and 120,000 men. They advanced as far as 12 kilometers (7 mi) into German-held territory in just seven hours. Erich Ludendorff referred to this day as “the Black Day of the German army”.
The offensive slowed and lost momentum due to supply problems. British units had encountered problems with all but seven tanks and trucks running out of fuel. On August 15, General Haig called a halt and began planning a new offensive in Albert. This Second Battle of the Somme began on August 21. Some 130,000 United States troops were involved, along with soldiers from Third and Fourth British Armies. It was an overwhelming success for the Allies. The Second German Army was pushed back over a 55 kilometer (34 mi) front, and by September 2, the Germans were back to the Hindenburg Line, which was their starting point in 1914.
The Allied attempt to take the Hindenburg Line (the Meuse-Argonne Offensive) began September 26, as 260,000 American soldiers went “over the top”. All divisions were successful in capturing their initial objectives, except the U.S. 79th Infantry Division, which met stiff resistance at Montfaucon and took an extra day to capture the objective. Then the US Army stalled because of supply problems as its inexperienced headquarters had to cope with large units and the difficult landscape (hilly and forested, with few roads).
At the same time, French units broke through Champagne and closed on the Belgian frontier. The most significant advance came from Commonwealth units as they entered Belgium (liberation of Ghent). The German army had to shorten its front so used the Dutch frontier as an anchor and chose to fight rear-guard actions. This probably saved the army from disintegration but was devastating for morale.
By the start of October, it was evident that Germany could no longer mount a successful defense, let alone a counterattack. Numerically on the frontline they were increasingly outnumbered, with the few new recruits too young or too old to be of much help. Rations were cut for men and horses because the food supply was critical. Ludendorff had decided, by October 1, that Germany had two ways out of the War—total annihilation or an armistice. He recommended the latter to senior German officials at a summit on that very same day. During October, the Allied pressure did not let up until the end of the war.
Meanwhile, news of Germany’s impending military defeat had spread throughout the German Armed forces. The threat of general mutiny was rife. Naval commander Admiral Reinhard Scheer and Ludendorff decided to launch a last ditch attempt to restore the “valor” of the German Navy. Knowing any such action would be vetoed by the government of Max von Baden, Ludendorff decided not to inform him. Nonetheless, word of the impending assault reached sailors at Kiel. Many rebelled and were arrested, refusing to be part of a naval offensive which they believed to be nothing more than a suicide bid. It was Ludendorff who took the blame for this—the Kaiser dismissed him on October 26. The collapse of the Balkans meant that Germany was about to lose its main supplies of oil and food. The reserves had been used up, but the Americans kept arriving at the rate of 10,000 a day. Stevenson, Cataclysm (2004) p 383.
With power coming into the hands of new men in Berlin, further fighting became impossible. With 6 million German casualties, Germany moved toward peace. Prince Max von Baden took charge of the new German government. Negotiations with President Wilson began immediately, in the vain hope that he would offer better terms than the British and French. Instead Wilson insisted on his Fourteen Points and demanded the abdication of the Kaiser. German soldiers were despondent. The civilian leadership was stunned to discover that Ludendorff had deluded them all along and there was no hope whatever for military success or even stalemate. Thus there was no resistance when the social democrat Philipp Scheidemann on November 9 declared Germany to be a republic. Von Baden then announced that the Kaiser was to abdicate, along with all other princes in the Reich. Imperial Germany was dead; a new Germany had been born: the Weimar Republic. Stevenson, Cataclysm (2004) ch 17.
==End of war==
The collapse of the Central Powers came swiftly. Bulgaria was the first to sign an armistice on September 29, 1918. On October 30, the Ottoman Empire capitulated. 
On October 24 the Italians began a push which rapidly recovered their territory a year after they lost it during the Battle of Caporetto. This push culminated in the Battle of Vittorio Veneto, which heralded the dissolution of the Austro-Hungarian Army as an effective fighting force. The push also triggered the disintegration of Austria-Hungary: during the last week of October declarations were made in Budapest, Prague and Zagreb, proclaiming the independence of their respective parts of the old empire. On October 29 the imperial authorities asked Italy for an armistice, but the Italians continued advancing reaching Trento, Udine and Trieste. On November 3 Austria-Hungary sent a flag of truce to the Italian Commander to ask again for an Armistice and terms of peace. The terms were arranged by telegraph with the Allied Authorities in Paris, were communicated to the Austrian Commander, and were accepted. The Armistice with Austria was signed in the Villa Giusti, near Padua, on November 3, and it was granted to take effect on November 4, at three o’clock in the afternoon. Austria and Hungary signed separate armistices following the overthrow of the Habsburg monarchy and the collapse of the Austro-Hungarian Empire.
Following the outbreak of the German Revolution, a republic was proclaimed on November 9, marking the end of the monarchy. The Kaiser fled the next day to the neutral Netherlands, which granted him political asylum (see Weimar Republic for details). On November 11, an armistice with Germany was signed in a railroad carriage at Compiègne in France where Germans had previously dictated terms to France, ending the Franco-Prussian War in 1871.
At 11:00am on November 11, 1918 — the eleventh hour of the eleventh day of the eleventh month — a ceasefire came into effect and the opposing armies on the Western Front began to withdraw from their positions. Canadian George Lawrence Price is traditionally regarded as the last soldier killed in the Great War: he was shot by a German sniper and died at 10:58.
A formal state of war between the two sides persisted for another seven months until it was finally ended by the signing of the Treaty of Versailles on June 28, 1919 with Germany, and the following treaties with Austria, Hungary, Bulgaria and The Ottoman Empire signed at St. Germain, Trianon, Neuilly and Sèvres. However, the latter treaty with the Ottoman Empire was followed by strife (the Turkish Independence War) and a final peace treaty was signed between the Allied Powers and the country that would shortly become the Republic of Turkey, at Lausanne on July 24, 1923.
Some war memorials date the end of the war as being when the Versailles treaty was signed in 1919; by contrast, most commemorations of the war’s end concentrate on the armistice of November 11, 1918. Legally the last formal peace treaties were not signed until 1923. Some also treat the Versailles treaty as the prelude to World War 2. 
==War crimes==
The ethnic cleansing of Armenians during the final years of the Ottoman Empire is widely considered a genocide. With World War I in progress, the Turks accused the (Christian) Armenians of preparing (or at any rate having the potential desire) to ally themselves with Russia, and used it as a pretext to deal with the entire Armenian population as an enemy within their empire. The exact numbers of deaths in the latter period is hard to establish. It is estimated by many sources that close to a million perished in camps, which excludes Armenians who may have died in other ways. Most estimates place the total number of deaths between 800,000 and 1.5 million. Turkish governments since that time have consistently rejected charges of genocide, typically arguing either that those Armenians who died were simply in the way of a war or that killings of Armenians were justified by their individual or collective support for the enemies of the Ottoman Empire.
==Economics and manpower issues==
Gross Domestic Product (GDP) increased for three Allies (Britain, Italy, and U.S.), but decreased in France and Russia, in neutral Netherlands, and in the main three Central Powers. The shrinkage in GDP in Austria, Russia, France, and the Ottoman Empire reached 30 to 40%. In Austria, for example, most of the pigs were slaughtered and, at war’s end, there was no meat.
All nations had increases in the government’s share of GDP, surpassing fifty percent in both Germany and France and nearly reaching fifty percent in Britain. To pay for purchases in the United States, Britain cashed in its massive investments in American railroads and then began borrowing heavily on Wall Street. President Wilson was on the verge of cutting off the loans in late 1916, but with war imminent with Germany, he allowed a massive increase in U.S. government lending to the Allies. After 1919, the U.S. demanded repayment of these loans, which, in part, were funded by German reparations, which, in turn, were supported by American loans to Germany. This circular system collapsed in 1931 and the loans were never repaid.
One of the most dramatic effects was the expansion of governmental powers and responsibilities in Britain, France, the United States, and the Dominions of the British Empire. In order to harness all the power of their societies, new government ministries and powers were created. New taxes were levied and laws enacted, all of which were designed to bolster the war effort; many of which have lasted to this day.
At the same time, the war strained the abilities of the formerly large and bureaucratized governments such as in Austria-Hungary and Germany. Here, however, the long term effects were clouded by the defeat of these governments.
Families were altered by the departure of many men. With the death or absence of the primary wage earner, women were forced into the workforce in unprecedented numbers. At the same time, industry needed to replace the lost laborers sent to war. This aided the struggle for voting rights for women.
As the war slowly turned into a war of attrition, conscription was implemented in some countries. This issue was particularly explosive in Canada and opened a political gap between the French-Canadians—who claimed their true loyalty was to Canada and not the British Empire—and the English-speaking majority who saw the war as a duty to both Britain and Canada, and a way of demonstrating leadership and high contribution to the British Empire. Prime Minister Sir Robert Borden pushed through a Military Service Act that caused the Conscription Crisis of 1917.
In Britain, rationing was finally imposed in early 1918 and was limited to meat, sugar and fats (butter and oleo), but not bread. The new system worked smoothly. From 1914 to 1918 trade union membership doubled, from a little over four million to a little over eight million. Work stoppages and strikes became frequent in 1917-18 as the unions expressed grievances regarding prices, liquor control, pay disputes, “dilution”, fatigue from overtime and from Sunday work, and inadequate housing. Conscription put into uniform nearly every physically fit man, six million out of ten million eligible in Britain. Of these, about 750,000 lost their lives and 1,700,000 were wounded. Most deaths were to young unmarried men; however, 160,000 wives lost husbands and 300,000 children lost fathers. [Havighurst p 134–5]
==Technology==
The First World War began as a clash of 20th-century wikipedia:technology with 19th-century tactics and the inevitable appalling casualties. By the end of 1917, however, the major armies — now numbering millions of men — had modernized significantly and were making use of such technology as wireless communication, armored cars, tanks, and tactical aircraft. The infantry was reorganized such that 100-man companies were no longer the main unit of manoeuver, in favor of the squad of 10 or so men under the command of a junior NCO. Artillery also had undergone a revolution; in 1914, cannons were positioned on the front lines and fired using open sights directly at their targets; by 1917, indirect fire with guns (as well as mortars and even machine guns) was responsible for the majority of casualties inflicted, and counter-battery artillery missions became commonplace, using new techniques for spotting and ranging enemy artillery. 
Much of the war’s combat involved trench warfare, where hundreds often died for each yard of land gained. Many of the deadliest battles in history occurred during the First World War. Such battles include Ypres, Vimy Ridge, Marne, Cambrai, Somme, Verdun, and Gallipoli. During the war, the Haber process of nitrogen fixation was employed to provide the German forces with a continuing supply of powder for the ongoing conflict in the face of British naval control over the trade routes for naturally occurring nitrates. Artillery was responsible for the largest number of casualties during the First World War, which consumed vast quantities of explosives. The large number of headwounds caused by exploding shells and shrapnel forced the combatant nations to develop the modern steel helmet. This effort was led by the French, who introduced the Adrian helmet in 1915. It was quickly followed by the Brodie helmet, worn by British Commonwealth and American troops, and in 1916 by the German Stahlhelm, the distinctive steel helmet that with improvements continued in use throughout World War II. 
There was chemical warfare and aerial bombardment, both of which had been outlawed under the 1907 Hague Convention, and both of which had extremely limited effects in tactical terms.
Chemical warfare was a major distinguishing factor of the war. Gases used included chlorine, mustard gas, and phosgene. Only a small proportion of total war casualties were caused by gas, but it achieved harassment and psychological effects by masking speech and slowing movement. Effective countermeasures to gas were quickly created in gas masks. Even as the use of gas increased, its effectiveness in creating casualties was quite limited.
The most powerful land weapons of the Great War were naval guns weighing hundreds of tons apiece (nicknamed Big Berthas by the British); they could be moved on land only by railroad. The largest U.S., British, and French rail guns were severely outranged by the German Krupp, Max E, and Paris Guns.
Fixed-wing aircraft were first used militarily during the First World War. Initial uses consisted of reconnaissance and ground attack. To shoot down enemy planes, anti-aircraft machine guns were used, and, more effectively, fast fighter aircraft. Strategic bombing aircraft were created principally by the Germans and British, though the former used Zeppelins to this end as well. 
Towards the end of the war, aircraft carriers were used in combat for the first time, with HMS Furious launching Sopwith Camels in a raid against the Zepplin hangars at Tondern in 1918.
German U-boats (submarines) were used in combat shortly after the war began. Alternating between restricted and unrestricted submarine warfare during the First Battle of the Atlantic, they were employed by the Kaiserliche Marine in a strategy of defeating the British Empire through a tonnage war. The deaths of British merchantmen and the invulnerability of U-boats led to the development of several countermeasures: depth charges (1916), hydrophones (passive sonar, 1917), blimps, hunter-killer submarines (HMS R-1, 1917), ahead-throwing weapons, and dipping hydrophones (both abandoned in 1918). To extend their operations, the Germans proposed supply submarines (1916). Most of these would be forgotten in the interwar period until World War II revived the need.
Trenches, the machine gun, air reconnaissance, barbed wire, and modern artillery with fragmentation shells helped bring the battle lines of World War I to a stalemate by making massed infantry attacks deadly for the attacker. The infantry was armed mostly with bolt-action magazine rifles, but the machine gun, with the ability to fire hundreds of rounds per minute, blunted infantry attacks as an offensive doctrine. The British sought a solution and created the tank, and with it mechanized warfare. The first tanks were used during the Battle of the Somme on September 15, 1916; mechanical reliability issues hampered their mobility, but the experiment proved its worth as protection against enemy weapons, particularly the machine gun. Within a year, the British were fielding tanks by the hundreds and showed their potential during the Battle of Cambrai in November 1917 by breaking the Hindenburg Line, while combined arms teams captured 8000 enemy soldiers and 100 guns. Light automatic weapons also were introduced, such as the Lewis Gun and Browning automatic rifle, combining the firepower of the machine gun with the portability of the rifle. 
Manned observation balloons floating high above the trenches were used as stationary reconnaissance points on the front lines, reporting enemy troop positions and directing artillery fire. Balloons commonly had a crew of two personnel equipped with parachutes; upon an enemy air attack on the flammable balloon, the balloon crew would parachute to safety. At the time, parachutes were too bulky to be used by pilots in aircraft, and smaller versions would not be developed until the end of the war. Recognized for their value as observer platforms, observation balloons were important targets of enemy aircraft. To defend against air attack, they were heavily protected by large concentrations antiaircraft guns and patrolled by friendly aircraft. Blimps and balloons helped contribute to the stalemate of trench warfare in World War I, and the balloons contributed to air-to-air combat among aircraft defending the skies and maintaining air superiority because of the balloons' significant reconnaissance value. The Germans conducted air raids on England and London during 1915 and 1916 using airships intending to damage British morale and will to fight, and to cause aircraft to be reassigned away from the front lines.
Another new weapon sprayed jets of burning fuel: flamethrowers. First used in war by the German army, and later adopted by other powers during WWI (it was invented prior to this, and simple models have existed since ancient times). Although not of high tactical value, they were a powerful, demoralizing weapon and caused much terror on the battlefield. It was a dangerous weapon to wield as their heavy weight made operators vulnerable targets, and the fuel on their backs was highly flammable.
==Aftermath==
The direct consequences of World War I brought many old regimes crashing to the ground, and ultimately, would lead to the end of 300 years of European hegemony in the world.
No other war had changed the map of Europe so dramatically—four empires disappeared: the German, Austro-Hungarian, Ottoman and the Russian. Four defunct dynasties, the Hohenzollerns, the Habsburg, Romanovs and the Ottomans together with all their ancillary aristocracies, all fell during the war. France was badly damaged, with 1.4 million soldiers dead, not counting other casualties. In addition, a major flu epidemic that started in Western Europe in the latter months of the war killed millions of people in Europe and then spread elsewhere around the world.
===Treaty of Versailles ===
Immediately after the war, the victors met in Paris and negotiated the Versailles Treaty. Germany was kept under a food blockade until it signed the treaty, which declared that Germany (and Austria) were guilty of starting the war and therefore had to pay all its costs. The treaty required Germany to pay enormous annual cash reparations, based on factors including the value of a soldier's life, which it did by borrowing from the United States, until reparations were suspended in 1931. The “Guilt Thesis” became controversial in Britain and the United States. It caused enormous bitterness in Germany, which nationalist movements, especially the Nazis, exploited in the 1920s. (See Dolchstosslegende).
===New national identities===
Poland reemerged as an independent country, after more than a century. Yugoslavia and Czechoslovakia were entirely new creations. Russia became the Soviet Union and lost several regions such as Finland, Estonia, Lithuania and Latvia which became independent countries. The old Ottoman Empire was soon replaced by Turkey and several other countries in the following years in the Middle East.
In the British Empire the war unleashed new forms of nationalism. In Australian and New Zealand popular minds, the First World War, specifically Gallipoli became known as the nations' “Baptism of Fire”, as it was the first major war in which the newly established countries fought, and it is one of the first cases in which Australian troops fought as Australians, not just subjects of the British Crown. Anzac Day commemorating the Australia New Zealand Army Corps is a defining moment. 
Similarly, Anglo-Canadians believe that they proved they were their own country and not just subjects of the British Empire. Indeed, many Canadians refer to their country as a nation “forged from fire,” as Canadians were respected internationally as an independent nation from the conflagrations of war and bravery. Canadians commemorate the war dead on Remembrance Day. However the French Canadians did not see it that way, creating a permanent chasm that continues to split the country. See Conscription Crisis of 1917 for more details.
===Social trauma===
The experiences of the war led to a sort of collective national trauma afterwards for all the participating countries. The optimism of the 1900s was entirely gone, and those who fought in the war became what is known as “the Lost Generation” because they never fully recovered from their experiences. For the next few years, much of Europe began its mourning; memorials were erected in thousands of villages and towns. The soldiers returning home from World War I suffered greatly, since the horrors witnessed in that war had never been seen before in history. Although it was then commonly called shell shock, it is now known that many returning soldiers suffered from Post Traumatic Stress Disorder. 
This social trauma manifested itself in many different ways. Some people were revolted by nationalism and what it had supposedly caused and began to work toward a more internationalist world, supporting organizations such as the League of Nations. Pacifism became increasingly popular. Others had the opposite reaction, feeling that only strength and military might could be relied upon for protection in a chaotic and inhumane world that did not respect hypothetical notions of civilization. “Anti-modernist” views were a reaction against the many changes taking place within society. The rise of Nazism and fascism included a revival of the nationalistic spirit of the prewar years and, on principle, a rejection of many postwar changes. Similarly, the popularity of the Dolchstosslegende was a testament to the psychological state of the defeated, as acceptance of the scapegoat mythos signified a rejection of the “lessons” of the war and therefore, a rejection of its popular resulting perspective. Certainly a sense of disillusionment and cynicism became pronounced, with nihilism growing in popularity. This disillusionment towards humanity found a cultural climax with the Dadaist artistic movement. Many people believed that the war heralded the end of the world as they had known it, including the collapse of capitalism and imperialism. Communist and socialist movements around the world drew strength from this theory and enjoyed a level of popularity they had never known before. These feelings were most pronounced in areas directly or particularly harshly affected by the war, especially within Europe.
In 1915, John McCrae, (a lieutenant colonel from the Canadian army), wrote the memorable In Flanders Fields as a salute to those who perished in the Great War. Its song is still played today, especially on Remembrance and Memorial Day.
==Other names==
World War I has also been called “The Great War” (a title previously used to refer to the Napoleonic Wars) or sometimes “the war to end all wars” until World War II.4 “War of the Nations” and “War in Europe” were commonly employed as descriptions during the war itself and in the 1920s. In France and Belgium it was also sometimes referred to as La Guerre du Droit ('the War for Justice') or La Guerre Pour la Civilisation / de Oorlog tot de Beschaving ("the War to Preserve Civilisation"), especially on medals and commemorative monuments. The term used by official histories of the war in Britain and Canada is First World War, while American histories use the term World War I. 
In many European countries, it appears that the current usage is tending back towards calling it "the Great War" / la Grande Guerre / de Grote Oorlog / der Grosse Krieg, due to the growing historical awareness that, of the two 20th-century world wars, the 1914-1918 conflict was the more momentous in causing social and political change and upheaval, as well as being prime cause of the Second World War.
==Movies, novels, poetry, etc.==
See main article Literature of World War I
====Poetry and songs====
* On Receiving News of the War, (1914) poem by Isaac Rosenberg
*In Flanders Fields, (1915) poem by John McCrae 
* Anthem for Doomed Youth, (1917) poem by Wilfred Owen
* Dulce et Decorum Est,(1917) poem by Wilfred Owen
* Disabled,(1917) poem by Wilfred Owen
* Base details,(1918) poem by Siegfried Sassoon
* They, (1918) poem by Siegfried Sassoon
* And The Band Played Waltzing Matilda, (1972) song by Eric Bogle
* Over There, (1917) theme song of the war by George M. Cohan
====Books and novels====
* Le Feu, (1916) novel by Henri Barbusse
* Storm of Steel, autobiography of Ernst Jünger. First published 1920 and revised several times through 1961
* Rilla of Ingleside (1920), novel by L.M. Montgomery, an account of the war as experienced by Canadian women of the time.
* Three Soldiers (1921) novel by John Dos Passos
* Seven Pillars of Wisdom (1922) by T. E. Lawrence
* The Good Soldier Švejk (1923) satirical novel by Jaroslav Hašek
* All Quiet on the Western Front (1929), novel written by Erich Maria Remarque
* Death of a Hero (1929) novel by Richard Aldington
* A Farewell to Arms, (1929) novel by Ernest Hemingway
* Goodbye to All That, (1929) autobiography of Robert Graves
* Memoirs of an Infantry Officer,(1930) novel by Siegfried Sassoon 
* Testament of Youth, (1933) memoir by Vera Brittain
* wikipedia:Johnny Got His Gun, (1939) novel by Dalton Trumbo
* Joe's War: Memoirs of a Doughboy (1983), autobiography by Joseph N. Rizzi
* Regeneration, (1991), The Eye in the Door, 1993; The Ghost Road novels by Pat Barker
* The Great Gatsby Fitzgerald
* Birdsong (1993), novel by Sebastian Faulks
* No Graves As Yet, (2003), first volume of a trilogy of novels by Anne Perry
* Deafening (2003), book written by Francis Itani
* A Long, Long Way (2005), novel by Sebastian Barry
* To the Last Man (2005), novel by Jeff Shaara
* Turn Right at Istanbul novel by Tony Wright
* A World Undone (2006), novel by G. J. Meyer
====Films, plays, television series and mini-series====
* Gallipoli (1981), movie directed by Peter Weir
* The Lighthorsemen (1987), movie directed by Simon Wincer
* The Four Horsemen of the Apocalypse (1921), movie directed by Rex Ingram, based on a novel by Vicente Blasco Ibáñez
* Mare Nostrum (1926), movie directed by Rex Ingram, based on a novel by Vicente Blasco Ibáñez
* Wings (1927), directed by William A. Wellman tells the story about two fighter pilots, only silent movie to win the Academy Oscar.
* Journey's End (1928), play written by R. C. Sherriff
* All Quiet on the Western Front (1930), movie directed by Lewis Milestone, based on the novel by Erich Maria Remarque (1929)
* Hell's Angels (1930), movie directed by Howard Hughes
* Grand Illusion (1937), directed by Jean Renoir
* Sergeant York (1941), movie directed by Howard Hawks
* Yankee Doodle Dandy (1942), directed by Michael Curtiz
* Paths of Glory (1957), movie directed by Stanley Kubrick, based on the novel by Humphrey Cobb (1935)
*Marš na Drinu (1961), Serbian war film about a Serbian artillery battalion in the Battle of Cer
* Lawrence of Arabia (1962), movie covering events surrounding T. E. Lawrence in the pan-Arabian Theater, starring Peter O'Toole, Alec Guinness, Anthony Quinn, and Omar Sharif and directed by David Lean
* World War I (1964), CBS News documentary narrated by Robert Ryan
* The Great War (1964) TV series by Correlli Barnett and others of BBC
*Doctor Zhivago (1965), movie by David Lean, based on the novel by Boris Pasternak, deals with Russia's involvement in the war and how it led to that country's Revolution.
* The Blue Max (1966), movie directed by John Guillermin, titled after the Prussian military award, or Pour le Mérite
* Oh! What a Lovely War(1969), movie directed by Richard Attenborough, from the 1963 musical play by Joan Littlewood
* Johnny Got His Gun (1971), movie directed by Dalton Trumbo
* Observe the Sons of Ulster Marching Towards the Somme, (1985), play by Frank McGuinness
* Blackadder Goes Forth (1989), TV series by Richard Curtis and Ben Elton
* Regeneration (1997), movie directed by Gillies MacKinnon, based on the novel by Pat Barker (1991)
* The Lost Battalion (2001), movie and screenplay directed by Russell Mulcahy
* A Very Long Engagement (2004), movie directed by Jean-Pierre Jeunet, based on the novel by Sebastien Japrisot (1991)
* Joyeux Noël (2005), Based on the 1914 Christmas truce.
* Passchendaele (2006), movie directed by and starring Paul Gross
*Flyboys (2006), Movie directed by Tony Bill, tells the story of American pilots who volunteered for the French military before America entered World War I.
== Footnotes ==
==References==
===Reference books===
* Ellis, John and Mike Cox. The World War I Databook: The Essential Facts and Figures for All the Combatants (2002)
* Esposito, Vincent J. The West Point Atlas of American Wars: 1900-1918 (1997) despite the title covers entire war; online maps from this atlas
* Higham, Robin and Dennis E. Showalter, eds. Researching World War I: A Handbook (2003), historiography, stressing military themes
* Pope, Stephen and Wheal, Elizabeth-Anne, eds. The Macmillan Dictionary of the First World War (1995)
* Tucker, Spencer, ed. The Encyclopedia of World War I: A Political, Social, and Military History (5 vol 2005), online at eBook.com
* Tucker, Spencer, ed. European Powers in the First World War: An Encyclopedia (1999)
* Winter, Jay, and Antoine Prost. The Great War in History (2005), historiography, stress on social and economic themes
===Overviews===
* Carver, Michael, Field Marshal Sir. War Lords. (1976) Includes brief bios of Hamilton, Foch, Haig, von Falkenhayn
* Cruttwell, C. R. M. F. A History of the Great War, 1914-1918 (1934), general military history
* Evans, David. Teach yourself— the First World War. (Hodder Arnold, 2004)
* Falls, Cyril. The Great War (1960), general military history
* Halpern, Paul G. A Naval History of World War I(1995) 
* Herwig, Holger H. The First World War: Germany and Austria-Hungary 1914-1918 (1996)
* Howard, Michael. The First World War (2002), short (175 pp) general military history
* Hubatsch, Walther. Germany and the Central Powers in the World War, 1914-1918 (1963)
* Keegan, John. The First World War (1999). general military history
* Lincoln, W. Bruce. Passage Through Armageddon: The Russians in War and Revolution, 1914-1918 (1986)
* Lyons, Michael J. World War I: A Short History (2nd Edition), Prentice Hall, 1999.
* Morrow Jr., John H.. The Great War: An Imperial History (2003), covers British Empire
* Robbins, Keith. The First World War (1993), short overview
* Stevenson, David. Cataclysm: The First World War As Political Tragedy (2004) major reinterpretation, 560pp
* Stokesbury, James. A Short History of World War I (1981)
* Strachan, Hew. The First World War: Volume I: To Arms (2004): the major scholarly synthesis. Thorough coverage of 1914; Also: The First World War (2004): a 385pp version of his multivolume history
* Winter, J. M. The Experience of World War I (2nd ed 2005), topical essays; well illustrated
===Causes and diplomacy===
* Evans, R. J. W., and Hartmut Pogge Von Strandman, eds. The Coming of the First World War (1990), essays by scholars from both sides
* Gilpin, Robert. War and Change in World Politics Cambridge University Press, New York: 1981.
* Hamilton, Richard F. and Holger H. Herwig. Decisions for War, 1914-1917 (2004)
* Henig, Ruth The Origins of the First World War (2002)
* Joll, James. The Origins of the First World War (1984)
* Kennedy, Paul M. (ed.). The War Plans of the Great Powers, 1880-1914. (1979)
* Kennedy, Paul M. The Rise of the Anglo-German Antagonism, 1860-1914 (1981)
* Knutsen, Torbjørn L. The Rise and Fall of World Orders Manchester University Press, 1999.
* Lee, Dwight E. ed. The Outbreak of the First World War: Who Was Responsible? (1958), readings from multiple points of view
* Ponting, Clive. Thirteen Days: Diplomacy and Disaster - The Countdown to the Great War (2002)
* Stevenson, David. The First World War and International Politics (2005)
=== Intelligence===
* Beesly, Patrick. Room 40 London: Hamish Hamilton, 1982. Covers the breaking of German codes by RN intelligence, Zimmermann telegram, and confusion at Jutland.
* Kahn, David. The Codebreakers Scribners, 1996. Covers the breaking of Russian codes and the victory at Tannenberg.
* David Kahn The Reader of Gentlemen's Mail: Herbert O. Yardley and the Birth of American Codebreaking (2004)
* Tuchman, Barbara W. The Zimmermann Telegram (1966)
=== USA and Canada at war===
* Beaver, Daniel R. Newton D. Baker and the American War Effort, 1917-1919 (1966)
* Chambers, John W., II. To Raise an Army: The Draft Comes to Modern America (1987)
* Coffman, Edward M. The War to End All Wars: The American Military Experience in World War I (1998)
* Hallas, James H. Doughboy War: The American Expeditionary Force in World War I (2000)
* Howarth, Stephen. To Shining Sea: A History of the United States Navy, 1775-1991 (1991)
* Kennedy, David M. Over Here: The First World War and American Society (1982), covers politics & economics & society
* Koistinen, Paul. Mobilizing for Modern War: The Political Economy of American Warfare, 1865-1919
* Slosson, Preston William. The Great Crusade and after, 1914-1928 (1930). U.S. social history
* Trask, David F. The United States in the Supreme War Council: American War Aims and Inter-Allied Strategy, 1917-1918 (1961)
* Venzon, Anne ed. The United States in the First World War: An Encyclopedia (1995)
* Milner, Marc, Prof. Canadian Military History. Toronto: Copp Clark Putnam, 1993. Includes problems of Canadian recruiting and the 1917 draft crisis (with its problems over Quebec)
* Morton, Desmond, and J. L. Granatstein Marching to Armageddon: Canadians and the Great War 1914-1919 (1989)
* Wade, Mason. The French Canadians, 1760-1945 (1955), ch 12
===Europe, economic and social===
* Broadberry, Stephen and Mark Harrison, eds. The Economics of World War I (2005) ISBN 0-521-85212-9. Covers France, UK, USA, Russia, Italy, Germany, Austria-Hungary, the Ottoman Empire, and the Netherlands
* Ferguson, Niall The Pity of War (1999), cultural and economic themes
* Hardach, Gerd. The First World War 1914-1918 (1977), economics
* Eric Osborne. Britain's Economic Blockade of Germany, 1914-1919 (2004)
* Stubbs, Kevin D. Race to the Front: The Materiel Foundations of Coalition Strategy in the Great War (2002)
* Shotwell, James T. Economic and Social History of the World War (1924)
* Turner, John, ed. Britain and the First World War (1988)
* Winter, J. M. The Experience of World War I (2nd ed 2005)
* Winter, J. M. Capital Cities at War: Paris, London, Berlin, 1914-1919 (1999)
=== Infantry and specialty military topics===
* Bidwell, Shelford, and Dominick Graham. Firepower: British Army Weapons and Theories of War, 1904-1945 (1992)
* Gudmundsson, Bruce I. Stormtroop Tactics: Innovation in the German Army, 1914-1918 (1989)
* Herwig, Holger H. Operation Michael: The “Last Card” 2001 German Spring Offensive in 1918
* Albert G. Love, War Casualties (1931) online statistics and how compiled for U.S. Army
* Messenger, Charles. Call To Arms: The British Army 1914-1918 (2005) (ISBN 0-297-84695-7), recruitment, training, supplying of officers & men
* Sheffield, G. D. Leadership in the Trenches: Officer-Man Relations, Morale and Discipline in the British Army in the Era of the First World War (2000)
* Smith, Leonard V. Between Mutiny and Obedience. The Case of the French Fifth Infantry Division during World War I (1994)
* Tuchman, Barbara. The Guns of August, tells of the opening diplomatic and military manoeuvres
=== New weapons, air, tank, gas, submarine===
====Air War====
* Holley, I. B. Ideas and Weapons: Exploitation of the Aerial Weapon by the United States During World War I(1983) 
* Hurley, Alfred F. Billy Mitchell, Crusader for Air Power (1975)
* Lawson, Eric and Jane Lawson. The First Air Campaign, August 1914-November 1918 (1996)
* Kennett, Lee B. The First Air War, 1914-1918 (1992)
* Morrow, John. German Air Power in World War I. Lincoln: University of Nebraska Press, 1982. Contains design and production figures, as well as economic influences.
* Winter, Denis. First of the Few. London: Allen Lane/Penguin, 1982. Coverage of the British air war, with extensive bibliographical notes.
====Gas====
* Haber, L. F. The Poisonous Cloud: Chemical Warfare in the First World War (1986);
* Palazzo, Albert. Seeking Victory on the Western Front: The British Army and Chemical Warfare in World War I (2000)
====Submarines====
* John Abbatiello. Anti-Submarine Warfare in World War I: British Naval Aviation and the Defeat of the U-Boats (2005)
* Gray, Edwyn A. The U-Boat War, 1914-1918 (1994)
* van der Vat, Dan. The Atlantic Campaign. (1988). Connects submarine and antisubmarine operations between wars, and suggests a continuous war.
====Tanks====
* Fuller Tanks in the Great War 1920.
* Guderian. Achtung! Panzer (1937)
* Wilson, Dale E. Treat'Em Rough!: The Birth of American Armor, 1917-20 (1989)
=== Popular histories and documentaries===
* Keegan, John. The First World War (1999)
* Taylor, A. J. P. The First World War: An Illustrated History, Hamish Hamilton, 1963
* Editors of American Heritage. History of WWI. Simon & Schuster, 1964. popular
* Johnny Got His Gun (1939) by Dalton Trumbo
* Strachan, Hew ed. The Oxford Illustrated History of the First World War, a collection of chapters from various scholars
* Toland, John. No Man's Land. 1918 - The Last Year of the Great War (1980)
* The Great War, television documentary by the BBC.
* Aces: A Story of the First Air War, written by George Pearson, historical advice by Brereton Greenhous and Philip Markham, NFB, 1993. Argues aircraft created trench stalemate
===Cultural, literary, artistic, memorial===
* Cruickshank, John. Variations on Catastrophe: Some French Responses to the Great War (1982)
* Eksteins, Modris, Rites of Spring: The Great War and the Birth of the Modern Age (1989).
*, classic study of WWI literature
* Bairnsfather, Bruce Bullets & Billets (1916) . Cartoons. 
* Hynes, Samuel. A War Imagined: The First World War in English Culture (1987)
*Mosse, George L. Fallen Soldiers: Reshaping the Memory of the World Wars (1991)
* Parfitt, George. Fiction of the First World War: A Study (London: Faber 1990). 
*Raitt, Suzanne and Trudi Tateeds. Women's Fiction and the Great War (1997)
*Remarque, Erich Maria. All Quiet On the Western Front
*Robb, George. British Culture And The First World War (2002)
*Roshwald, Aviel. European Culture in the Great War : The Arts, Entertainment and Propaganda, 1914-1918 (2002)
*Silkin, Jon. ed. The Penguin Book of First World War Poetry (2nd ed. 1997)
*Stallworthy Jon. Great Poets of World War I: Poetry from the Great War (2002), brief
*Vance, Jonathan F. Death So Noble: Memory, Meaning, and the First World War (1997)
*Verhey, Jeffrey. The Spirit of 1914: Militarism, Myth and Mobilization in Germany (2000)
* Viney, Nigel. Images of Wartime: British Art and Artists of World War I (1991)
* Watson, Janet S. K. Fighting Different Wars: Experience, Memory, and the First World War in Britain (2004).
* Winter, Jay. Sites of Memory, Sites of Mourning: The Great War in European Cultural History (1995), 
*Wood, Richard and David Culbert. Film and Propaganda in America: A Documentary History: World War I - Vol. 1 (1990)
==See also==
* List of World War I veterans
* Surviving Veterans of the First World War
* British military rifles
* List of Canadian divisions in WWI
* War memorials
===Main articles===
* World War II
==External links==
* A Guide to World War I Materials at the Library of Congress
* Chronology World War I World History Database
* A multimedia history of World War I
* The War to End All Wars on BBC
* “The Heritage of the Great War” with numerous pictures (many in color!)
* Royal Engineers Museum The Royal Engineers and the First World War
* GenealogyBuff.com — World War I Casualty Reports for the U.S. Army 1918
* The British Army in the Great War
* A history of opposition to the war in Britain
* The French Army in the Great War
* World War I — Wars And Battles
* Fighting the Hun in the Great War
* Encyclopedia of the First World War
* Trenches on the Web
* Online World War I Records & Indexes
* World War I Document Archive
* The Medical Front WWI
* World War I Naval Combat
* Wanted! 500 000 Canadians for WWI — Illustrated Historical Essay
* Memoirs of the Great War — A personal account in diary format of one man’s experiences throughout the Great War
* War diaries of TF Littler A personal account, war postcards and propaganda comic postcards
* Mediatheque Autochromes — French site with many color photographs from WWI
* The World War I Years — NVR’s Film & Discussion Series in Public Libraries
* WWW-VL: Military History: The Great War 1914-1918
* WWI links
* Chailey 1914-1918 - A Sussex community's response to the First World War
* canadiansoldiers.com
*World War I Poster Collection hosted by the Universtity of North Texas Libraries' Digital Collections
*German submarine industries WWI
*Documents of World War One
*First World War in the News
*The Great War in a Different Light Photographs, illustrations, postcards, artists, period newspaper and magazine articles/excerpts, complete war-time books. Material in English, French, Dutch, German, Spanish
*
World War I