Leonardo da Vinci’s armored vehicle was designed to move using cranks.
The fighting vehicle, sketched in the 1480s, resembles a conical armored shell mounted on wheels. Inside, men would turn hand-operated cranks connected through gears to the wheels. The armor was intended to protect the crew while the vehicle approached enemy positions, and the platform was designed to carry several light cannons around its perimeter.
The design is often called Leonardo's tank, but that label can make it sound more modern than it was. It had no engine, tracks, turret, or internal combustion system. A famous drawing also contains a likely gearing problem: if built exactly as shown, the wheels would turn in opposing directions. Historians debate whether this was an error, a deliberate safeguard, or a result of Leonardo's presentation. Regardless, the machine illustrates his interest in combining armor, mobility, weapons, and mechanical transmission in one battlefield device.