World War I, 1914-18, also called the Great War, conflict, chiefly in
Europe, among most of the world’s great powers. On one side were the Allies
(chiefly France, Britain, Russia, and the U.S.); on the other were the
Central Powers (Germany, Austria-Hungary, and Turkey). Prominent among the
war’s causes were the imperialist, territorial, and economic rivalries of
the great powers. The German empire in particular was determined to
establish itself as the preeminent power on the Continent. The Germans were
also intent on challenging the naval superiority of Britain. However, it
was rampant nationalism-especially evident in the Austro-Hungarian empire-
that furnished the immediate cause of hostilities. On June 28, 1914,
Archduke FRANCIS FERDINAND, heir apparent to the Austro-Hungarian throne,
was assassinated at Sarajevo by a Serbian nationalist. One month later,
after its humiliating demands were refused, Austria-Hungary declared war on
Serbia. Other declarations of war followed quickly, and soon every major
power in Europe was in the war. On the Western Front, the Germans smashed
through Belgium, advanced on Paris, and approached the English Channel.
After the first battles of the MARNE and YPRES, however, the Germans became
stalled. Grueling trench warfare and the use of poison gas began all along
the front, and for the next three years the battle lines remained virtually
stationary despite huge casualties at VERDUN and in the Somme offensive
during 1916. On the Eastern Front, the Central Powers were more successful.
The Germans defeated (Aug.-Sept. 1914) the Russians at Tannenberg and the
Masurian Lakes. Serbia and Montenegro fell by the end of 1915. In the
south, the Italian campaigns were inconclusive, though they benefited the
Allied cause by keeping large numbers of Austrian troops tied down there.
In Turkey, the Allies’ ambitious Gallipolli Campaign (1915), an attempt to
force Turkey out of the war, was a costly failure. In the Middle East, T.E.
LAWRENCE stirred Arab revolt against Turkey. U.S. neutrality had been
threatened since 1915, when the British ship LUSITANIA was sunk. By 1917
unrestricted German submarine warfare had caused the U.S. to enter the war
on the side of the Allies. An American Expeditionary Force, commanded by
Gen. PERSHING, landed in France and saw its first action at Chteau-Thierry
(June 1917). In Mar. 1918 the new Soviet government signed the Treaty of
BREST-LITOVSK with the Central Powers. The Germans were stopped just short
of Paris in the second battle of the Marne, and an Allied counteroffensive
was successful. The Turkish and Austro-Hungarian empires, disintegrating
from within, surrendered to the Allies, as did Bulgaria. After revolution
erupted in Germany, the armistice was signed on Nov. 11, 1918. The Treaty
of VERSAILLES and the other treaties that ended the war changed the face of
Europe and the Middle East. Four great empires-Germany, Austria-Hungary,
Russia, and Turkey-had disappeared by the end of the war. Replacing them
were governments ranging from monarchies and sheikhdoms through
constitutional republics to the Marxist socialist state of the USSR. The
war itself had been one of the bloodiest in history, without a single
decisive battle. A total of 65 million men and women had served in the
armies and navies; an estimated 10 million persons had been killed and
double that number wounded. Such statistics contributed to a general
revulsion against war, leading many to put their trust in multinational
disarmament pacts and in the newly formed LEAGUE OF NATIONS.