Austria begins an offensive against Italy, Russia gears up a counteroffensive in Galicia, and the British and German Navies have it out in the Skagerrak.

The fighting continued at Verdun as the Russians prepare an offensive of their own to relieve the pressure on France. A German U-boat mistakenly sinks a passenger ferry in the English Channel, triggering another controversy over submarine rules of engagement.

The third year of the war opens with Britain and Germany as the mainstays of their respective alliances. The German Chief of Staff tries a bank shot: cripple Britain by wounding France.

Turkish forces defeat a British force attempting to take Baghdad, but that doesn't stop the British and the French from divvying up the postwar Middle East. Also, the Russians advance, the Italians don't.

Venustiano Carranza is gaining momentum in the struggle over the future of Mexico, but Pancho Villa is not ready to give up. The Germans hope to lure the US into intervening, then Pancho Villa decides provoking the US is also in his interests.

In the neutral United States, the economy is booming and so is the motion picture business. And the most famous name in pictures is Charles Chaplin.

Allied commanders on the Western Front spent 1915 developing new strategies for the Great War, and attempted to implement them in their autumn offensive.

With numbers of new volunteers declining every month, the British government wrestles with the issue of conscription. Across Europe, all the Great Powers are feeling the manpower and other shortages created by the war.

After the overthrow of Victoriano Huerta, the revolutionary forces in Mexico begin fighting among themselves, and Huerta himself conspires with the Germans to return to power.

Albert Einstein needed ten years to flesh out his special theory of relativity into a general theory of relativity, but when he finished, he changed our understanding of the nature of reality itself.