What armored vehicle did Leonardo da Vinci design with a conical cover and gun ports?

Leonardo da Vinci designed an armored tank-like fighting vehicle with a conical cover and gun ports.

The machine appeared in a drawing from around 1487–1488. Its protective shell was shaped like a turtle’s carapace and was intended to shield soldiers while they operated cannons arranged around the vehicle. The design also included wheels driven by internal mechanisms.

Historians often call it Leonardo’s fighting vehicle rather than a modern tank, because it was never constructed as a functioning armored vehicle and lacked an engine. A famous drawing also appears to contain a gear arrangement that would make the machine move backward, although this may reflect a drafting error or deliberate concealment.

The concept is important because it combines armor, mobility, and concentrated firepower centuries before modern tanks. It should not be described as the first operational tank.