Which Leonardo da Vinci machine is a famous early concept for a tank?

Leonardo da Vinci’s armored vehicle is a famous early concept for a tank.

Leonardo designed the vehicle in the 1480s while working for Ludovico Sforza in Milan. The drawing shows a conical, turtle-like armored cover fitted with sloping plates. Inside, men would turn cranks connected to wheels, allowing the machine to move while protecting its occupants from enemy fire. The vehicle was intended as a battlefield weapon rather than a transport vehicle.

It was never built in Leonardo’s time. Some modern commentators point out that the drawing appears to contain a gearing problem that would make the proposed vehicle move backward. Whether that was an error, a deliberate flaw, or a detail Leonardo expected to correct remains debated. The design still matters historically because it combines armor, wheels, crew protection, and mounted weapons in a form later associated with tanks.