12th century cathedral or se. ---- Huge cathedral founded in the 12th century but extensively altered in the 18th. Open from 9am to 12:30 and 2:30 to 7. Igreja de Sao Francisco ---- Gothic church with a plain facade but tons of gold-leaf gilding inside. There is also a museum and catacombs below, which we found more fascinating than many guidebooks did. Ponte de D.---- Luis, the city's emblematic iron bridge, built by a disciple of the famous Eiffel. Don't miss the Ribeira do Porto, ---- the cluster of buildings, smoky bars and seafood restaurants along the waterfront.