Ponte de Dom Luis I 
Description
The bridge is the main link between Porto and Gaia, linking the waterfront at Ribeira with the port wine lodges. The bridge is a strange construction with the main deck running across the top of the structure at the same hight as the cathedral, with a much lower deck suspended beneath it. The top deck is open to pedestrians and the Metro line D, lower deck is the main road to the waterfront and heavily used by tour and service buses. As the bridge faces almost due West it's a popular place to visit to watch the sunset.
Charge
Free
Getting There
Latitude: 41.139956; Longitude: -8.609423
What3Words: wheels.balanced.coast
