Barcelona hides 2,000 years under its pavements: a Roman colony founded around 10 BC, a medieval Mediterranean naval empire, 1714's siege that ended Catalan self-rule, and 1930s bomb shelters. This guide follows that layered chronology street by street.
Descend 4 metres below Plaça del Rei into 4,000 m² of excavated Roman Barcino: laundry vats, a garum fish-sauce factory, a 4th-century wine press and early Christian basilica, all under the medieval Palau Reial. Tue–Sat 10:00–19:00, Sun to 20:00.
Catalan Gothic at its purest: built 1329–1383 in just 54 years by the bastaixos, the port dockers who carried the stone from Montjuïc on their backs — carved into the bronze doors. Anarchists burned the interior in 1936, leaving bare stone. €6 entry.
The 13th-century royal shipyards, the largest surviving medieval industrial building in Europe, with stone naves 33 m long. Centrepiece: the full-scale replica of the Royal Galley that led the fleet at Lepanto in 1571, 60 m and 236 oarsmen.
Barcelona's medieval Jewish quarter, home to some 4,000 people until the pogrom of August 1391 destroyed it. Alleys barely a metre wide; the Hebrew foundation stone on Carrer Marlet reads 'pious foundation of Rabbi Samuel Hasareri'.
The 1751 fortress rebuilt after the 1640 revolt, its guns aimed at the city rather than the sea. Franco's forces executed Catalan president Lluís Companys here on 15 October 1940. The moats and bastions are walkable; ramparts give the whole port in one sweep.
A former quarry turned mass grave: some 4,000 people shot by the Franco regime between 1939 and 1952 were buried here anonymously. Companys's tomb sits at the centre of the memorial garden laid out in 1985. Open daily, free, almost always empty.
Under an 1876 iron market hall lie the excavated streets of the Ribera district, flattened after Barcelona fell on 11 September 1714 to build the Ciutadella fortress. You look down on actual house floors, wells and cellars, frozen mid-18th-century.
Philip V's punitive citadel of 1716 stood here until 1869, when the city tore it down; only the chapel, arsenal and governor's palace survive. The park then hosted the 1888 Universal Exposition, for which Josep Vilaseca built the Mudéjar-brick Arc de Triomf.
400 m of hand-dug tunnels where up to 2,000 neighbours sheltered from Italian bombers during the 1937–39 raids that killed some 2,500 Barcelonans. Original latrines, infirmary and children's room survive. Guided visits only, Sundays, in Catalan, Spanish and English.
Four fluted Corinthian columns, 9 m tall, from the temple to Augustus that crowned Mont Tàber, Barcino's 16.9 m summit — marked by a millstone in the doorway. They stand in the courtyard of a medieval house, hidden until 1835. Free entry.
Shrapnel scars pit the church wall on Plaça Sant Felip Neri, where a Fascist bomb killed 42 people, mostly children, on 30 January 1938. Ten minutes west, Sant Pau del Camp is Barcelona's oldest church, Romanesque, consecrated 1117, with a tiny cloister.
The 15th-century archdeacon's house holds the city archive: charters, guild records and the Llibre del Consolat de Mar. Its Modernista marble letterbox of 1895, carved by Domènech i Montaner with a swallow and a tortoise, sits by the door. Free courtyard.