What vehicle did Leonardo da Vinci design with sloped armor and hidden mechanisms?

Leonardo da Vinci designed an armored vehicle with sloped protective plates and concealed mechanisms.

The machine appears in Leonardo’s notebooks as a covered, conical vehicle intended to move across a battlefield while protecting the people inside. Its sloping armor could help deflect attacks, and the design included multiple weapons arranged around the vehicle.

The vehicle is often called Leonardo’s tank, but that modern label can obscure its historical context. It was not a tracked tank and did not operate like a twentieth-century armored fighting vehicle. The proposed machine would have been powered by people turning cranks connected to wheels.

A famous drawing also contains a likely mechanical problem: some interpretations note that the gears would turn in opposing directions. This may have been deliberate, a drafting error, or evidence that the design was never intended for immediate construction. The invention remains an important early armored-vehicle concept.