The Luís I Bridge (Ponte de Dom Luís I) is a two-tier iron bridge spanning the Douro River between Porto and Vila Nova de Gaia, designed by Théophile Seyrig, a former student and collaborator of Gustave Eiffel. Built between 1881 and 1886, its 172-meter central arch made it the longest of its kind in the world when it opened.
The upper deck, at 45 meters above the river, carries Porto’s Metro line D alongside a pedestrian walkway with sweeping views over the Ribeira district’s colorful riverside houses and the port-wine cellars of Gaia. The lower deck, closer to the water, carries road traffic and a second pedestrian path, making the bridge equally scenic from either level.
Crossing the bridge is free and open around the clock, since it functions as a working transit route rather than a ticketed attraction. Sunset is the most popular time to walk the upper deck, when the terracotta rooftops and river below take on a golden glow.