Leonardo da Vinci designed a giant crossbow with a bow nearly 27 metres wide.
The design appears in Leonardo’s military studies from the late fifteenth century. It was intended to create fear and launch a large projectile, but its enormous size made it impractical as a conventional hand-held crossbow. Leonardo’s drawings show a broad bow mounted on a wheeled structure, with mechanical equipment for drawing the string.
Unlike an ordinary crossbow, the giant design would have required a substantial frame and a powerful loading mechanism. Leonardo explored military machines as part of his work for powerful patrons, presenting devices that combined engineering ingenuity with dramatic battlefield impact.
The design is sometimes confused with ancient artillery such as the ballista. A ballista is a separate torsion-powered weapon, whereas Leonardo’s machine retained the essential bow-and-string arrangement of a crossbow. There is no reliable evidence that this giant weapon was built and used in battle.