What military vehicle did Leonardo da Vinci design with sloped armor and a circular body?

Leonardo da Vinci designed an armored vehicle with sloped armor and a circular body. Often called Leonardo’s fighting vehicle, it resembles a conical tank and was intended to move across a battlefield while protecting its crew.

The wooden vehicle has an outer shell covered with metal plates and several light cannons arranged around its circumference. Leonardo’s drawings show a crew inside turning cranks connected to wheels. The sloped surfaces could help deflect incoming projectiles, while the circular plan offered weapons a broad field of fire.

The machine had serious practical problems. The proposed gearing appears to make the wheels turn in opposite directions, although some historians think this may have been deliberate concealment or a copying error. The vehicle was never built for Renaissance warfare.

Calling it a tank can be useful as a modern comparison, but “armored vehicle” is the safer historical description. Modern tanks use engines, tracks or specialized wheels, armor, and weapons in ways Leonardo’s hand-powered concept did not.