What type of bridge did Leonardo da Vinci propose for Sultan Bayezid II in 1502?

Leonardo da Vinci proposed a single-span bridge for Sultan Bayezid II in 1502.

The design was intended to cross the Golden Horn near Constantinople, today Istanbul. Leonardo’s proposal used a broad masonry span with a flattened, pointed-arch profile and no support pier in the water. The unusually wide opening would have allowed ships to pass beneath it.

Sultan Bayezid II did not accept the proposal, and Leonardo’s bridge was not built in the Renaissance. The surviving letter and drawing nevertheless show an ambitious attempt to solve a difficult crossing with a single structural span.

In 2001, a smaller pedestrian bridge based on Leonardo’s concept was built in Ås, Norway. It was not the original Golden Horn bridge and should not be confused with the modern Galata Bridge. Leonardo’s design belongs to the history of bridge engineering, even though it remained a proposal.