Museu d'Historia de Barcelona (MUHBA)

This is the perfect setting for a museum of city history. The Casa Padellas, a 15th-century Gothic merchant’s palace was painstakingly moved to this site in 1931 to make way for the new Vía Laietana. While digging its foundations, workers uncovered a surprise: houses of Roman and Visigothic Barcino, stretching beneath the modern C/ de los Comtes, complete with a 4th-century baptistry.

These layers of the ancient Barcino – the largest underground excavations of any ancient city in Europe – were left remarkably intact; here you can look down on roads marked by wheel ruts gouged out two millennia ago. Traces of indigo dye still stain the stone vats of the laundry and dying workshops, which were later incorporated into the baths, equipped with a gymnasium and massage rooms.