Bolshevik leader V. I. Lenin publishes Imperialism, the Highest Stage of Capitalism, expanding on ideas first expressed by British liberal John Hobson in his Imperialism (1902).

Edward A. Sharpey-Schafer, an English physiologist, coins the name insulin for a hormone produced by the pancreas.

24 Jan.

Great Britain adopts compulsory military service, with exceptions for conscientious objectors.

21 Feb.

German troops begin a major offensive against Allied positions at Verdun, on the Meuse River in northern France. This battle becomes the longest battle of the war, lasting until December and claiming 435,000 German casualties and more than 540,000 French casualties.

5 Mar.

The Allies invade German East Africa.

8 Mar.

Mexican rebel Pancho Villa raids Columbus, New Mexico. In retaliation Woodrow Wilson orders U.S. troops commanded by John J. Pershing to pursue Villa into Mexico. The troops are withdrawn in February 1917, having failed to capture Villa.

9 Mar.

Germany declares war on Portugal.

Great Britain and France...