The Plaza de Armas of Santiago, located in the commune of Santiago, is the historic center of the capital of Chile. It is bounded by the streets Catedral and Monjitas to the north, 21 de Mayo and Estado to the east, Compañía and Merced to the south, and the promenades Ahumada and Puente to the west. Under the square is located the Plaza de Armas subway station, inaugurated in 2000 for line 5 and in 2019 for line 3.

The history of this space dates back to the pre-Hispanic period, when, according to research by the National Museum of Natural History and the Andrés Bello University, there was an Inca settlement in the old part of Santiago, which used hydro-agricultural and mining systems. This infrastructure would have been used by Pedro de Valdivia to found the city in 1541. Designed in a grid layout similar to a chessboard by Pedro de Gamboa, the square was the nucleus where the main administrative buildings were located. During colonial times, it became an important market and the site of public execution. In 1825, it was renamed Plaza de la Independencia, although it later recovered its original name of Plaza de Armas. From 1859, the square was transformed into a green space with gardens, and in 1896 the French landscaper Guillermo Renner designed a park with trees and ponds. In 1872, the extension of streetcars turned the square into a convergence point, and in 1973 it was the site of the first LGBT demonstration in Chile.

Between 1998 and 2000, the construction of the metro station prompted a renovation of the square, which included cultural areas and a pergola for musical performances. In 2014, a remodeling was carried out to expand the green areas, install LED lighting, surveillance cameras and free wifi network, and it was reopened in December of that year with the presence of park rangers. In its surroundings are important buildings such as the Metropolitan Cathedral, built in 1748 and remodeled in the nineteenth century, as well as the Central Post Office, the National Historical Museum and the Municipality of Santiago. In front of the square is located the Portal Fernandez Concha, a shopping center with food stores and stores. In addition, in the nearby streets there is an area known as "Little Lima" for the presence of stores oriented to the Peruvian community.

The Plaza de Armas also houses several monuments, such as the equestrian statue of Pedro de Valdivia, the Monument to American Freedom, the Monument to the Original Peoples, the statue of the Apostle Santiago and the Bicentennial Capsule, as well as several plaques on the ground commemorating Kilometer Zero, the historical plans of the city and the visit of John Paul II.