Leonardo da Vinci designed an armored tank as a circular, covered fighting vehicle powered by rotating wheels and operated by soldiers inside.
His design, drawn around 1487–1490, resembles a conical turtle shell covered with metal plates. Several men inside would turn cranks connected to the wheels, while cannons projected through openings around the vehicle. The design was intended to protect its crew while advancing toward enemy forces.
The vehicle was never built in Leonardo’s lifetime, so it is more accurate to call it a proposed armored fighting vehicle than a working historical tank. A modern reconstruction also revealed that the original drawing may contain a gearing error that would prevent the wheels from turning correctly unless corrected.
Leonardo’s design is often called a tank because it anticipates the basic idea of an armored vehicle, but it lacked an engine, tracks, and modern steering. The first operational tanks appeared centuries later during World War I.