2 Best Sights in Lisbon, Portugal

More than 2,500 years of history are on display beneath a bank on one of Lisbon's busiest streets. A subterranean network of tunnels occupies almost a whole block in Lisbon's historic center and was unearthed in the 1990s during excavation works carried out by the bank Millennium BCP, which revealed homes and artifacts from the Roman, Visigoth, Islamic, medieval, and Pombaline periods. Much of the space was used as a major-scale Roman fish-salting factory. It was later used as a Christian burial ground, and there's even a well-preserved skeleton to be seen. Free 50-minute guided tours (book in advance) in English or Portuguese lead through the underground walkways.  

The Carmelite Convent—once Lisbon’s largest—was built in 1389 by Nuno Álvares Pereira to give thanks for Portugal’s victories over Castile. It was all but destroyed in the 1755 earthquake, leaving the haunting shell of a Gothic church that still stands today. The former sacristy houses the Museu Arqueológico do Carmo, a compact but intriguing collection of Gothic tombs, Roman epigraphy, medieval tiles, and ancient coins. Outside, the tree-shaded Largo do Carmo connects to the top platform of the Elevador de Santa Justa and is a tranquil spot for a coffee or cocktail. But this peaceful setting belies its dramatic history: it was here, at the adjacent Carmo barracks, that Prime Minister Marcelo Caetano took refuge during the 1974 Carnation Revolution. He eventually surrendered to rebel troops, marking the end of the dictatorship. Today, the Museu da Guarda Nacional Republicana (closed Sunday and Monday) occupies the barracks and includes the historic room where Caetano made his final stand.