Mexican archaeologists say they have found an unprecedented human burial in which the skeleton of a young woman is surrounded by piles of 1,789 human bones in Mexico City's Templo Mayor.

Researchers found the burial about five meters (15 feet) below the surface, next to the remains of what may have been a "sacred tree" at one edge of the plaza, the most sacred site of the Aztec capital.

The National Institute of Anthropology and History said the find was the first of its kind, noting the Aztecs were not known to use mass sacrifice or the reburial of bones as the customary ways to accompany the interment of a member of the ruling class....