Watch WWI: The First Modern War Season 1 Online

Tanks were the first armored fighting machine to be used on the battlefield. These "land ships", as they were first called, were championed by Head of the British Admiralty Winston Churchill. Adapted from an American tractor with caterpillar tracks, the machine was designed in secrecy to break through the heavily fortified trenches and offer protection for troops that were being mowed down by heavy artillery.