What rotating military bridge did Leonardo da Vinci design for rapid river crossings?

Leonardo da Vinci designed a revolving bridge for rapid military river crossings.

The bridge was intended to pivot around a central support, allowing soldiers to move it into position and then swing it away when necessary. Leonardo’s drawings show how mechanical movement could make a bridge portable and useful in changing battlefield conditions.

The design belongs to his broader work on military engineering, which included fortifications, weapons, transport devices, and siege machinery. A revolving bridge could reduce the time needed to cross a waterway compared with building a fixed crossing from scratch.

This design is different from Leonardo’s self-supporting bridge. The self-supporting version used interlocking beams and did not depend on a pivot. The revolving design instead emphasized controlled rotation around a support point, making the two bridge concepts easy to confuse.