The fossils of an unknown species from the genus Homo (where humans belong) has been discovered inside a South African cave.
Archaeologists found 1,500 bones belonging to 15 individuals.
Skeletons ranged from babies to elderly individuals. They have been found in a remote, hardly accessible region of a large cave.
Archaeologists believe the bodies have been placed there deliberately or maybe a 'death trap' scenario occurred in which they got trapped and couldn't escape.
Archaeologists say that the skeletons could be anything between 20,000 and 2 million years old.
The remains were found in the Rising Star cave system in South Africa's Gauteng province. They were in a remote chamber that can only be accessed via several steep climbs and fissures some as narrow as 10 inches.
The chamber, situated down a narrow 40 feet (12 metre) chute, is around 30 feet (9 metres) long and just a few feet wide.
A few Homo naledi's features were very similar to those of modern humans.
Professor Chris Stringer, research leader in Human Origins at the Natural History Museum, London, said: 'The deep cave location where the bones were found suggests that they may have been deposited there by other humans, indicating surprisingly complex behavior for a 'primitive' human species.'
Professor Chris Stringer also said: 'On the other hand, the species' small brain and the shape of its upper body are more similar to a prehuman group called australopithecines.'
The shape of the skull, shape and structure of feet, shape and structure of hands, palms and wrists and long legs are similar to modern humans.
Size of skull, 'flared' hips, curved fingers useful for climbing trees and shoulders suggest swinging from trees.
Archaeologists hope Homo naledi will reveal answers on the transition from australopithecines to humans.
Archaeologists said that it could take decades before they identify who Homo naledi really was and how he fits into humanity's complex evolutionary tree.
Casts of Homo naledi fossils will be unveiled at the Natural History Museum's event on the 25th of September. They will go on permanent display at the end of November.