In trench warfare, the two sides fighting each other dug trenches in a battlefield. These trenches had many different parts, such as places for sleeping, for headquarters, for storage, and for artillery and machine guns. Between the front trenches on a battlefield, was an area called "no man's land". This area was often covered with barbed wire and land mines. Soldiers on either side would try to cross the no man's land to get to the enemy's trench and attack. Tanks were commonly used to cross this land.