What self-propelled machine did Leonardo da Vinci design in 1478?

Leonardo da Vinci designed a self-propelled cart in 1478.

The machine was powered by coiled springs concealed inside its wooden body. When released, the springs turned the wheels through a system of gears. A steering mechanism allowed the cart to follow a preset path, making it suitable for theatrical performances or ceremonial displays.

The cart is often called an early ancestor of the automobile, but it was not powered by an engine and could not operate indefinitely. Its exact reconstruction became possible after historians studied Leonardo’s drawings and noticed that earlier interpretations had missed important details. A working replica was built in Italy in 2006.