Leonardo da Vinci designed an armored tank with a conical shell and room for eight soldiers.
His fighting vehicle was a covered, turtle-like platform surrounded by sloping armor. The shape was intended to deflect incoming projectiles, while a set of cannon openings allowed the occupants to fire outward. Leonardo's notes describe a crew of eight men operating the vehicle.
The machine was meant to move with wheels driven by internal cranks. A commonly repeated story says Leonardo deliberately included a gearing error to prevent the design from being used against him, but historians debate whether the mismatch was intentional or simply a mistake in the drawing. The vehicle was never built in Leonardo's lifetime. It resembles a tank in its protected, mobile fighting role, but it lacked the engines, tracks, turret, and modern armor associated with twentieth-century tanks.