What vehicle did Leonardo da Vinci design with an armoured, conical shell?

Leonardo da Vinci designed an armoured vehicle with a conical shell.

The machine appears in Leonardo’s military engineering studies from the late fifteenth century. Its sloped outer covering was intended to deflect incoming projectiles, while openings around the shell would allow weapons to be fired outward. The vehicle was designed to be moved by people turning internal cranks connected to wheels.

It is often called Leonardo’s tank, but that modern label can be misleading. The design predates engines, tracks, and the armored fighting vehicles used in twentieth-century warfare. It was a proposed war machine rather than a documented battlefield vehicle, and there is no firm evidence that Leonardo’s version was built in his lifetime.

A frequently repeated story says Leonardo deliberately included a flaw in the gearing to prevent the machine from being used. Historians debate that interpretation; the drawing’s mechanism may simply reflect an error or an incomplete design. The vehicle remains notable for its armor, rotating weapon positions, and crewed enclosure.