This viewpoint (miradouro) is on the Vila Nova de Gaia side of the river, right next to the famous Ponte Luis I bridge. Bang for buck this is probably the best view of Porto as it takes in so many of the key locations.
Obviously you can't miss the bridge, as it is right next to the viewpoint, and you are looking straight across to the Ribeira with the historic city centre rising steeply behind. To the left the Douro curves away before heading under the Arrabida Bridge. Plus you can see a few of the Port Lodges on the near bank of the river, with some of the iconic rabelos (port boats) alongside.
