Since the mid-17th century, when the Jesuits established themselves on the block bounded by the present-day streets of Bolívar, Moreno, Perú, and Alsina, Monserrat has been a hub of intellectual life. The Jesuits were the most intellectual of monastic orders, but they were also the most commercial—the two surviving buildings of the Procuraduría, fronting on Alsina, stored products from their widespread missions, housed missionized Indians from the provinces, and contained defensive tunnels.

After the Jesuits’ expulsion from the Americas in 1767, the buildings served as the Protomedicato, which regulated medical practice in the city; but the block later housed, in succession, a public library, a medical school, and various university departments. After 1974 the Comisión Nacional de la Manzana de las Luces attempted to salvage them for cultural purposes, opening the tunnels to the public and restoring part of the “Universidad” lettering along the Perú facade.

The Iglesia San Ignacio (1722) replaced an earlier structure of the same name. In 1836 the Jesuits returned, at Rosas’s invitation; in 1955, at Juan Perón’s instigation, mobs trashed the building, but it has since been restored.

The church shares a wall with the Colegio Nacional de Buenos Aires (1908), the country’s most prestigious and competitive secondary school, taught by top university faculty. The re-created Sala de Representantes housed the province’s first legislature.

The Instituto de Investigaciones Históricas de la Manzana de las Luces Doctor Jorge E. Garrido (Perú 272, tel. 011/4342-3964, www.manzanadelasluces.gov.ar) conducts a series of guided tours (1 and 3 p.m. Mon.; 3 p.m. Tues.–Fri.; 3, 4:30, and 6 p.m. Sat.–Sun.) for US$1.50 pp. English-language tours (US$3 pp) require 15 days’ notice and a minimum of 20 people.