Known. Children found a mummy about 7,000 years old in the ground by a beach.
The place is Morro de Arica, on El Laucho beach, in northern Chile. The mummy belongs to the Chinchorro people, whose culture is dated from about 7020 BC to 1500 BC. Chinchorro mummies are the oldest human-made mummies yet known.
The page says no one knows the exact reason they mummified their dead.