The grandest square in Lisbon, opening directly onto the Tagus through a waterfront arcade. The Marquis of Pombal designed it after the 1755 earthquake as the ceremonial heart of the rebuilt city — government ministries occupy the flanking arcaded buildings, and the equestrian statue of José I commands the centre. The triumphal arch on the north side leads to Rua Augusta and the Baixa grid beyond.
Today the square is busy with tourists, trams, and the Lisbon Story Centre (a multimedia history museum in the western wing). The riverside terrace is a good place to watch the ferries crossing to the south bank. At sunset the light across the Tagus is extraordinary. The square is also the endpoint of some of the most dramatic protests in Portuguese history — most notably on 25 April 1974, when the Carnation Revolution ended 40 years of dictatorship.