Palacio San Martín

This imposing Beaux-Arts-style palace was built for Mercedes Castellanos, a local high-society lady who also funded the construction of the Basilica of the Blessed Sacrament. The building was completed in 1909 and became the property of the Argentine government in 1936, which turned it into the Ministry of Foreign Affairs. Today, it is mainly used for official events. If you'd like to see its interior and learn more about its history, you can book a free guided tour, available in Spanish only. You'll see some amazing rooms and artwork by several 20th-century American artists.