"Fragments of human bones that exhibit cut marks and prolonged exposure to fire have been discovered through various excavations in the Sacred Precinct of Tenochtitlan (located in Mexico City). These skeletal remains are from individuals, such as children, slaves and captured warriors, who were sacrificed during religious festivals." Source: Past Horizons.
Comment: Blood sacrifice was an integral part of ancient religions around the world and it's still a central concept in Christianity, which is built around the sacrificial death and rebirth of Jesus, and to Islam with its cult of martyrs.
The Aztecs knew how ritual sacrifice worked, obviously, unlike the modern "pagans" who stage drum circles at Stonehenge or the "light warriors" who planted "muffin-crystal thingies" at Serpent Mound last year in an attempt to "lift the vibrations."