What enormous weapon did Leonardo da Vinci sketch with a bow spanning about 25 meters?

Leonardo da Vinci sketched a giant crossbow designed with a bow spanning about 25 meters.

The enormous weapon appears in Leonardo’s military-engineering studies from the late fifteenth century. Its scale was intended to create a powerful projectile weapon capable of intimidating opponents and striking targets at a distance. Leonardo also considered mechanisms for drawing and releasing the bowstring, since human strength alone would not have been enough.

The design was never known to have been built or used in battle. Its large dimensions made it more a demonstration of mechanical ambition than a practical field weapon. Artists and engineers sometimes call it a giant crossbow, while the term ballista is used for other ancient or crossbow-like siege weapons.

Leonardo’s military notebooks include many proposed weapons, but surviving drawings do not prove that every design reached construction.