36 hours in Porto, Portugal

A view over the museums in the World of Wine district, with the Dom Luis I Bridge in the distance, in Porto, Portugal. First Lisbon; now Porto. The whole world seems to have fallen in love lately with the nearby beaches, old churches, seafood-heavy cuisine and historical UNESCO-listed streets of Portugal’s second-largest city, where the number of tourists has doubled in a decade. (The circuslike atmosphere along the Douro riverfront and outside Livraria Lello, a neo-Gothic 19th-century bookstore, are only the most obvious signs.) And the home of port wine...