World War I broke out on Tish’ah B’Av 5674 (1914) and lasted until 7 Kislev 5679 (November 11, 1918). The “Great War,” as it was known, pitted the armies of Germany, Austria-Hungary, and the Ottoman Empire (the Central Powers) against Great Britain, France, Russia, Italy, and Japan (the Allied Powers). The Allies were joined after 1917 by the United States. The four years of the Great War saw unprecedented levels of carnage and destruction, thanks to grueling trench warfare and the introduction of modern weaponry such as machine guns, tanks, and chemical weapons. By the time World War I ended in the defeat of the Central Powers in November 1918, more than nine million soldiers had been killed and 21 million more civilians wounded.