He designed a tank more than 400 years before it became a reality

Da Vinci built a battle machine in 1487 that is now known as Leonardo's tank or Leonardo's fighting vehicle. The machine, which had 36 weapons jutting out from its sides and a conical cover inspired by a turtle's shell, required eight men to operate. A set of gears would drive the system, which would be powered by cranks that rotated a series of wheels. A military team developed a working machine from Leonardo's tank design by replacing one of the gears, an error allegedly done on purpose to prevent it from being utilized by unauthorized persons, according to a BBC documentary. As a result, Da Vinci conceived the tank 400 years before it was utilized in the First World War.

Da Vinci's drawings, which originate from roughly 1485, vividly demonstrate how his innovations were based on his extensive understanding of nature. The vehicle's conical cover, in the instance of Da Vinci's tank, was clearly inspired by a turtle's shell, an appropriate armor. This outside covering was supposed to be constructed of wood, but it was supposed to be reinforced with metal plates to provide thickness. Those with slanting angles would efficiently deflect enemy fire (an engineering trick rediscovered after World War I). The war machine was built to be pushed straight onto the battlefield, with two massive inner cranks controlled by four powerful soldiers.