The Luís I Bridge (Ponte Luís I) is a metal arch bridge that spans the Douro River between the cities of Porto and Vila Nova de Gaia in Portugal. At the time of construction its span of 172 m was the longest of its type in the world. Téophile Seyrig was working as a partner of Eiffel. He took sole responsibility for the new, major Luís 1st Bridge. The construction was begun in 1881 and the bridge opened on 31 October 1886.