Porto, Ponte Maria Pia

The Maria Pia Bridge (in Portuguese Ponte de D. Maria Pia, commonly known as Ponte de Dona Maria Pia) is a railway bridge built in 1877, and attributed to Gustave Eiffel, situated over the Portuguese northern municipalities of Porto and Vila Nova de Gaia.

Part of the Linha Norte system of the national railway, the wrought iron, double-hinged, crescent arch spans 353 m (1,158 ft), 60 m (200 ft) over the Douro River. At the time of its construction, it was the longest single-arch span in the world; today, it is no longer used for rail transport and was replaced by a modern structure in 1991. It is often confused with the D. Luís Bridge, which was built nine years later and is located 1 kilometre (0.62 mi) to the west, but resembles the structure, albeit with two decks.

Source: en.wikipedia.org/wiki/Maria_Pia_Bridge