Museo de Arqueología de la Alta Montaña
The main sight in the city of Salta is the Museo de Arqueologia de Alta Montaña, which houses three mummified Inca children, who were found frozen at an altitude of 22,000 feet at the top of Llullaillaco volcano.
They were discovered in 1999 by an Argentine-US expedition funded by the National Geographic Society. Nature had preserved them from the day of their death in a frozen state, and they had 146 objects with them. I think global warming must have melted the ice around them, which was essential for their discovery. The museum was built for them and each child was on display in a glass freezer.
Prof. Johan Reinhard was the American co-leader of the expedition. This is his gallery link:
http://www.kodakgallery.com/reinhard/main/argentina_-_llullaillaco_discoveries_la