The Praça do Comércio (Portuguese pronunciation: [ˈpɾasɐ du kuˈmɛɾsju]; English: Commerce Square) is a large, harbour-facing square in Portugal's capital, Lisbon, being one of the largest in Portugal, with 175 by 175 m (574 by 574 ft), that is, 30,600 m2 (329,000 ft2).
Facing the Tagus (Tejo) to the South, the city square is still commonly known in Portuguese as Terreiro do Paço ([tɨˈʁɐjɾu du ˈpasu]; English: Palace Yard), as it hosted the Paço da Ribeira (Royal Palace of Ribeira) until it was destroyed by the great 1755 Lisbon earthquake (the subway station located there is still called after the old name of the square).
After the earthquake, the square was completely remodeled as part of the rebuilding of the Pombaline Downtown (Baixa), ordered by Sebastião José de Carvalho e Melo, 1st Marquis of Pombal, who was (chief) Minister of Portugal from 1750 to 1777, during the reign of the Portuguese King José I.From the 19th century onwards, Praça do Comércio became the seat of some of the most important Portuguese state departaments, including the Ministries of Finances, Internal Affairs, Agriculture and Sea; before the Carnation Revolution (1974) and the creation of a unified Ministry of Defence, it was also the location of the War and Navy Ministries, as well as the old Ministry of Colonies (up to 1967), thus becoming a methonym for the Portuguese central government. Furthermore, the Supreme Court is also housed there.
In June 1910, just a few months before the establishment of the Portuguese Republic, Praça do Comércio was classified as a National Monument of Portugal.