The imperious, double-decker metal spans of Ponte de Dom Luís I stretch across the Douro River from Porto to Villa Nova de Gaia, and were designed by Téophile Seyrig, the student of Gustave Eiffel who also drew up the plans for the nearby Donna Maria Pia Bridge. When the Dom Luís I was finished in 1886, it was the longest single-span bridge in the world at 564 feet, and it supported 3,045 tons of steel in weight.
The bridge marked a significant step forward in Porto’s economic growth, as before it existed, the only passages across the river were boats lashed together. Today the lower deck of the bridge carries cars while the upper level is utilized by metro Line D and has a pedestrian walkway offering views across the river. Since the late 19th century, four other bridges have joined the bridge of Dom Luís I and Donna Maria Pia in reaching across the Douro; they are all best seen by river cruise in a traditional wooden rabelo.