What weapon did Leonardo da Vinci design with a bow nearly 27 metres wide?

Leonardo da Vinci designed a giant crossbow with a bow nearly 27 metres wide.

The enormous weapon appears in Leonardo’s sketches from the late 15th century. Its exceptional size was intended to increase the range and power of the projectile, while a winch or mechanical loading system would help draw the bowstring.

The design was probably never built as a practical battlefield weapon. Leonardo often created spectacular military machines for patrons, combining workable mechanisms with imaginative scale. His notebooks contain several other siege-engine concepts, including catapults and large crossbows.

The giant crossbow is sometimes confused with Leonardo’s multi-barrel gun design. They were separate projects: the crossbow relied on stored tension in a bow, whereas the other weapon used repeated gun barrels.