Casa Torre Tagle
This viceregal-era mansion sums up the graceful style of the early 18th century. Flanked by a pair of elegant balconies, the stone entrance is as expertly carved as that of any of the city's churches, while the patio is a jewel of the Andalusian baroque, with slender columns supporting delicate Moorish arabesques. The Casa Torre Tagle currently holds offices of the Foreign Ministry and is open to the public only occasionally, but if your timing is serendipitous, you can check out the tiled ceilings of the ground floor and see the house's 18th-century carriage. Across the street is Casa Goyeneche, built some 40 years later in 1771 and clearly influenced by the rococo movement.