Battle of the Somme

The Battle of the Somme (French: Bataille de la Somme), also known as the Somme Offensive, took place during the First World War between 1 July and 18 November 1916 in the Somme department of France, on both banks of the river of the same name. The battle consisted of an offensive by the British and French armies against the German Army, which since invading France in August 1914 had occupied large areas of that country. One of the largest battles of the First World War, by the time fighting had petered out in late autumn 1916 more than 1.5 million casualties had been suffered by the forces involved. It is understood to have been one of the bloodiest military operations ever recorded.

http://en.wikipedia.org/wiki/Battle_of_the_Somme