Porto
Porto Travel Guide: Port Cellars and the Douro
Porto in two or three days: Ribeira and the bridges, the port cellars in Gaia, azulejo tiles, and whether the Douro Valley is worth a day.
Porto Travel Guides
Porto coverage runs from the Ribeira riverfront and Vila Nova de Gaia's port cellars to the Douro Valley trips upriver, with the walking routes, viewpoints and timing that make a two or three day stay work.