Tower of 650 human skulls found near ancient Aztec temple

A tower of over 650 skulls has been discovered near the site of Templo Mayor, one of the main temples in the Aztec capital Tenochtitlan, which later became Mexico City. The skulls represent ritualistic sacrifices as offerings to the Sun by Aztec ethnic groups of Mexico, archaeologists said. More skulls would be unearthed as the excavations go on, they added.