I recently visited Porto with some friends and a major highlight was experiencing the Dom Luis I bridge.
The bridge crosses the river Douro and connects the historical city of Porto with the port wine warehouses of Vila Nova de Gaia. At the time of construction, the Dom Luis I arch bridge had the longest span of its type, at 172 meters. In total, the bridge is just over 385 meters long.
The bridge features an upper and lower deck, with the upper level reserved for a light metro line and pedestrians, while the lower level is for general traffic and pedestrians.
The bridge was designed by Teophile Seyrig, a partner of Gustav Eiffel at the time, and many guidebooks will wrongly attribute the design of the bridge to Gustav Eiffel.
Following is a picture I was able to capture: