Neither the passage of time nor the enmity of the Franco government could kill this classic eatery just off Puerta del Sol. Founded in 1860, Casa Labra remains unrepentantly old-fashioned with its polished dark wood and blue-and-white tiles, looking just as it did when it was a popular gathering spot for Franco’s Republican enemies during the Civil War. The specialty of the house is bacalao (salt cod), the fish that’s been the foundation of Spanish cuisine at least since the first restaurants opened in Madrid in the 19th century. Stop in the taberna (really, the bar) for bite-sized tapas of fried fresh cod or a small plate of bacalao croquetas. The dining room menu runs the gamut of cod dishes, from a woodsy version with wild mushrooms, capers, and orange juice, to a more ethereal presentation with saffron and rice. Another historic footnote: The Spanish Socialist Workers’ Party (PSOE) was founded here in 1879.