Perhaps Buenos Aires’s most photogenic building, the former waterworks (1894) glistens with 170,000 rust-colored tiles and 130,000 enameled bricks imported from Britain, crowned by a Parisian mansard. Filling an entire city block, the extravagant exterior masks a utilitarian interior of 12 metallic tanks that held more than 60 million liters of potable water.

Swedish architect Karl Nystromer conceived the building, popularly known as Obras Sanitarias, whose tanks became superfluous as engineers developed subterranean tunnels for moving water through the city. At present, the building houses offices and the small but interesting Museo del Patrimonio Aguas Argentinas (tel. 011/6319-1104), a museum open 9 a.m.–1 p.m. weekdays only, with free guided tours at 11 a.m. Monday, Wednesday, and Friday. The tanks now hold archives of city maps and plans that were created in conjunction with the waterworks.

The official street address is Riobamba 750, but the museum entrance is on the Rivadavia side; follow the arrows to the elevator, which takes you to the 1st floor.