Key Facts about the Battle of the SommeThe Battle of the Somme (1 July - 18 November 1916) was one of the most bitterly contested and costly battles of the First World War, lasting nearly five months. The offensive began on 1 July 1916 after a week-long artillery bombardment of the German lines. There were over a million casualties on both sides and by the end of the campaign the British had only advanced seven miles. This infographic gives some key facts about the battle.