Leonardo da Vinci designed a pontoon bridge to help armies cross rivers quickly.
A pontoon bridge rests on floating supports rather than permanent masonry piers. Leonardo's bridge concepts used lightweight structural parts that could be transported, assembled, and deployed for military movement. His drawings show his interest in making bridges portable and stable while reducing the time needed to cross a water obstacle.
Leonardo was not the first person to use floating bridges. Armies had constructed temporary bridges from boats, rafts, and other buoyant supports long before the Renaissance. His contribution was to study improved forms and include practical details for construction and transport.
Modern pontoon bridges continue to use the same broad principle, although they employ engineered floats, modular roadway sections, and stronger connectors. Leonardo's bridge work is therefore best understood as an inventive development in military engineering, not the invention of every floating bridge technique.