Archaeologists in Peru have uncovered the remains of 25 people in the ancient city of Chan Chan.
The skeletons were found in a small space measuring 10 sq m in what was once the capital of the Chimú empire.
The Chimú ruled parts of present-day Peru. Their empire reached its height in the 15th Century before their defeat by the Incas.
Chan Chan, where the mass grave was found, was the largest mud citadel in pre-Columbian America.
Experts think that the mass grave may have been a burial place where members of the Chimú elite were laid to rest.
Archaeologist Sinthya Cueva told Reuters news agency said that most of the remains belonged to young women. "None of them are over 30 years old."
While it is known that the Chimú carried out human sacrifices, including of children, archaeologist Jorge Meneses Bartra said that there was no evidence those in the newly discovered grave died that way.