Tanks were created by Lancelot de Mole. Tanks were used by many different militaries.

During World War 1 militaries used tanks for many reasons. Tanks were used for taking out anything in their path, including buildings. Tanks were also used to kill the enemies.  Tanks had guns on them to shoot enemy soldiers and the tanks would run over enemy soldiers as well. When friendly soldiers were in war they had hid behind the tanks for cover. 

Tanks are important for many reasons. One reason was for clearing out trenches and WWI was fought from trenches.  Since soldiers could not walk between their trench and the enemy trench without being noticed and killed, tanks allowed for protected movement into enemy territory.  This new technology changed the way the war was fought.