Anti-tank trenches, also called anti-tank ditches, are ditches dug into and around fortified positions to hold up the advance of enemy tanks. Anti-tank ditches were first used in World War I by Germany in an effort to protect their trenches against the newly developed British tanks. An anti-tank ditch has to be wide enough and deep enough to prevent a tank from crossing. Armies have been known to disguise anti-tank ditches to enable the ditch to disable an enemy tank.