What land vehicle did Leonardo da Vinci sketch with sloped armor and cannon openings?

Leonardo da Vinci sketched an armored vehicle with sloped protection and cannon openings.

The drawing, usually called Leonardo’s fighting vehicle, shows a conical or turtle-shaped armored body mounted on wheels. Its sloping armor was intended to deflect incoming projectiles, while openings around the vehicle allowed guns to fire outward. The machine was conceived as a mobile platform for approaching enemy forces.

The vehicle’s movement depended on internal cranks and gears operated by people inside. One famous feature of the drawing is that the gear arrangement appears to be incorrectly configured, causing the wheels to turn in opposite directions. Historians debate whether this was an error, a deliberate concealment, or an unfinished design.

Calling it a tank is useful as a modern comparison, but Leonardo’s machine was not a twentieth-century tank. It had no engine, and the proposed crew-powered mechanism would have faced serious practical limits. The drawing is best described as an armored vehicle or fighting vehicle concept.