Leonardo da Vinci's armored vehicle design is commonly called Leonardo's tank.
Leonardo drew the design around 1487–1489. It was a conical, turtle-shaped fighting machine with sloping armor intended to deflect enemy fire. The vehicle contained benches and hand-operated cranks connected to wheels, allowing several people inside to drive it.
The drawing is often described as an early tank concept, but it was never built in Leonardo's lifetime. A well-known problem in the surviving design is that some gears appear to be arranged so the vehicle could not move correctly. Historians and engineers have suggested that this may have been deliberate, accidental, or a result of copying errors.
Leonardo's tank was therefore a theoretical armored vehicle, not a functioning modern tank. The first operational tanks appeared during World War I, more than four centuries later. Leonardo's design is still important because it combines armor, mobility, crew protection, and mounted firepower in one recognizable concept.