Ponte Luiz I, Porto

Ponte Luiz I is the iron bridge that links Porto with Vila Nova de Gaia across the Douro. Take in the airy latticework and the immense curve carrying its paired decks: when it was built, its arch spanned 172 metres, making it the world’s longest of that kind. Construction ran from 1881 to 1886, replacing an earlier suspension bridge at this crossing.

Belgian engineer Théophile Seyrig designed it; he had previously worked with Gustave Eiffel on the nearby Maria Pia railway bridge, which explains the family resemblance. The bridge is named for King Luís I of Portugal. Since 2005, the upper deck has carried Metro line D as well as people on foot, while the lower deck serves public transport, taxis, cyclists, and pedestrians. It is both a working crossing and a defining piece of Porto’s industrial heritage.