Leonardo da Vinci's armoured vehicle was designed to resemble a turtle from above. Its conical, armoured shell was intended to protect soldiers while the vehicle moved across a battlefield.
Leonardo drew the fighting vehicle around 1487 for the ruler of Milan, Ludovico Sforza. The design placed cannons around the sloping outer shell, allowing the crew to fire in several directions while remaining sheltered inside.
The vehicle was meant to be driven by people turning internal cranks connected to the wheels. Some modern reconstructions have noted that the gear arrangement in the famous drawing appears mechanically inconsistent, possibly because Leonardo deliberately concealed or altered part of the design.
Although often called Leonardo's tank, it was not a modern tank: it had no engine, tracks, or demonstrated battlefield use. The turtle-like shape reflected the defensive purpose of the armoured shell rather than a claim that the machine copied a real animal mechanically.