Leonardo da Vinci’s armored tank design required eight men to operate it.
Leonardo sketched the fighting vehicle in the 1480s while working for Ludovico Sforza in Milan. The machine had a conical, turtle-like armored shell and was intended to advance across a battlefield while its occupants operated weapons mounted around the platform.
Eight men inside the vehicle would turn cranks connected to the wheels. The arrangement was meant to provide propulsion while protecting the crew from enemy fire. The design also included a circular platform carrying light cannons or guns, giving the vehicle an all-around firing capability.
The vehicle was never built for Renaissance warfare. A famous drawing contains a gear arrangement that appears to make the wheels turn in opposite directions, leading to claims that Leonardo deliberately sabotaged the design. Historians also note that the apparent problem may have resulted from the sketch’s technical limitations or from later interpretation.