Luís I Bridge is an arch bridge that crosses the River Douro in Porto, Portugal. The bridge was designed by Téophile Seyrig who previously worked for Gustave Eiffel. Gustave Eiffel designed Maria Pia bridge which is also in Porto.
Construction of Luís I bridge started in 1881 and the bridge was opened in 1886. When the bridge opened with a span of 172 meters, it was the largest arch bridge in the world until 1898.
In the upper deck runs Metro do Porto tram and in the lower deck is traffic.