The machine built to win the First World War - built in 1941 !
If you are into Steampunk/Dieselpunk games, here is an opportunity to deploy a landship that was actually built.
Variously code-named as "White Rabbit No.6", "Cultivator No.6", "Naval Land Equipment" (NLE, "Nellie"), it was built on the insistence of Winston Churchill himself, designed to plow towards enemy positions, creating a trench wide enough for troops and vehicles to march through.
Wikipedia has more information about the original.