During the turn of the 20th century and before Santiago's elite packed it up and moved away from the downtown hubbub, Calle Dieciocho ranked as the city's toniest neighborhood. The tourism board touts Calle Dieciocho as a step back in time, but neglect has taken its toll, and the only site really worth visiting here is the Palacio Cousiño Macul, once the home of Chile's grandest entrepreneurial dynasties, the Goyenechea-Cousiño family. A visit here (by guided tour only) provides a unique opportunity to appreciate how Santiago's elite lived during the late 1800s. Once completed in 1878, the palace dazzled society with its opulence: lavish parquet floors, Bohemian crystal chandeliers, Italian hand-painted ceramics, and French tapestries. Much of the building was destroyed by fire in the 1960s but what remains provides a dizzying insight into the excellence of European craftsmanship at the turn of the 19th century. To get here, you can either take a taxi or the Metro (Estación Toesca). If you'd like to take a walk, then by all means do begin at Avenida Alameda and head down Calle Dieciocho for 15 minutes, until you reach the Palace (you might begin with lunch at the legendary Confitería Torres and then walk it off down Dieciocho). Also, take a 10-minute detour around the corner from Cousiño Macul (east on San Ignacio) to Parque Almagro, a scruffy park that nevertheless affords a view of the little-known, almost Gaudiesque Basílica del Santísimo Sacramento church, constructed between 1919 and 1931 and modeled after the Sacre Coeur in Montmartre, Paris.