Archaeologists digging at the ruins of Pachacamac in Peru say they have discovered a multi-level burial site.
Mummies of different epochs were among the finds
Mummy bundles of entire families were found in the graves from various eras, built on top of each other, they say.
The researchers described the find as "exceptional" as the previously ignored cemetery had not been looted and is completely intact.
Pachacamac, south of the capital, Lima, is thought to have been ruled by the Ychsma lords from 900 to 1470.
The Incas turned it into a place of pilgrimage and it was abandoned after the Spanish conquest. Today, the sprawling ruins attract many tourists.
Peter Eeckhout, who heads the team of archaeologists working there, said the discovery would help to reveal how different cultures used the area.
"We have encountered superimposed burials - so one beneath the other - which represent several different cultures and periods of the site," he said.
The Incas turned Pachacamac into a place of pilgrimage
Some 69 tombs have been excavated in the area.
Mr Eeckhout said mummies of different epochs, including mummy bundles containing whole families, were among the finds.
The excavations, which began in 1999, are part of Project Ychsma.
Mr Eeckhout said the conditions of many of the remains suggest that, at one stage in history, ill people came to the area to seek cures for their ailments, perhaps from an oracle.
"In the upper layer of burials, we have an abnormal proportion of individuals who were suffering from very grave and lethal diseases, such as syphilis, tuberculosis and cancer," he said.