The Chachapoya people were a tribe that flourished until they were conquered and assimilated into the Inca culture around 1470 CE. Oner type of artifact they left behind was their purunmachus, or sarcophagi. These were built high on cliff faces so they wouldn't be looted.
A trove of these purunmachus were discovered in 1928 when an earthquake brought one down into the Utcubamba valley. More have been found since then, in several styles. It is believed that a deceased body would be placed on a cliff ledge and then the purunmachu was built around it.
(Image credit: Flickr user Nick Leonard)