The small mining town of San Antonio de los Cobres is located in the Andean puna (highlands) province of Salta in northwest Argentina. Though it is home to some charming adobe (mud brick) buildings, San Antonio de Los Cobres is a curious destination in that its chief attraction lies in the rail trip it requires to access the town. The Tren a las Nubes (‘Train to the Clouds’) is the third-highest railway line in the world and is one of the provinces of Salta’s most unforgettable travel experiences. These day trips offer spectacular Andean scenery, and an exciting ride as the train passes over 29 bridges and through 21 tunnels from the city of Salta to the La Polvorilla Viaduct.