Photo Gallery Europe's Great Conflagration
German troops advancing across open ground at Villers-Bretonneux during Germany's last major effort to secure victory on the Western Front. Germany had hoped a quick victory over France would propel it to victory against Russia.
The war made little sense even at the time and was primarily the result of large powers attempting to prove their dominance over the Continent. Here, German machine gunners defending a position near the Italian-Slovenian border in 1917.
A group of royals at the end of the 19th century. Many of the leaders of the big European powers on the eve of World War I were related. In this 1894 picture, the Prince of Wales, later to become King Edward VII, can be seen on the back-right. Next to him stands Wilhelm II, the emperor of the German Reich.
World War I was the first fully industrialized conflict. Among its horrors was also one of the first uses of poison gas in warfare. Here, gasmasks for German soldiers and their dogs are being tested.
A mounted army patrol reconnoiters in the Alsace region in 1915. Much of Europe is marking the centennial of the beginning of World War I this year.
Kaiser Wilhelm II has long been blamed for playing a key role in starting World War I by granting the Austro-Hungarian Empire his support for an invasion of Serbia.
A German trench is seen in occupied Poland in 1915. New research is questioning the long-held view that Germany was alone responsible for starting World War I. Historians are not exonerating Kaiser Wilhelm II, but the failures of other players are being highlighted.
Stretcher bearers carry a wounded soldier in Flanders. The Western Front saw some of the most violent and deadly battles ever seen in the history of warfare.
German and Austrian prisoners of war in 1918. At the time World War I began, war was seen as a legitimate tool of foreign policy.
The war ended on Nov. 11, 1918 at 11 a.m. The armistice treaty was signed in a rail car in the forest of Compiègne.
