A long many-arched bridge designed to carry a road or railway over a river and its floodplain.

Viaduct over the River Finghorn in Scotland.

Viaducts were built on the same basic design as aqueducts by the Romans, using semicircular arches to support the top deck of the viaduct.

The building of a viaduct is a major undertaking and after Roman times few were made until the Industrial Revolution. By this time new materials were available and viaducts were then made from iron and steel. Reinforced concrete viaducts are now the most common kind.