Porto

Porto is Portugal's most photogenic city: terracotta rooftops cascading down to the Douro, six bridges spanning the river, and Vila Nova de Gaia's port wine cellars on the south bank. The Ribeira district (UNESCO-listed) is the postcard image, but the real Porto reveals itself in the azulejo-tiled churches, the Lello bookshop (Harry Potter's reputed inspiration), and the working-class taverns serving francesinha sandwiches. The headline experience is a Douro Valley day trip from Porto: river cruise, vineyard lunch, and tastings at two or three quintas. The valley is the world's oldest demarcated wine region and the scenery — terraced vineyards plunging to the river — is breathtaking. Closer to the city, six-bridges cruises take 50 minutes and are the best way to grasp Porto's geography. Porto's best months are May, June, September, and October: warm but not hot, low rain, and the wine harvest at the end of September. Winter is mild (10-15°C) but expect rain.