Introduction
Praça do Comércio is Lisbon's grand riverside square on the Tagus estuary, built after the 1755 earthquake and traditionally known as Terreiro do Paço. Its landmark is the Arco da Rua Augusta, a triumphal stone arch completed in 1875 at the entrance to Rua Augusta, which visitors can climb for panoramic views over the square, the river, and downtown Lisbon.