Sixteen feet (five meters) below street level in Mexico City, archaeologists have found a jumble of 1,789 bones from children, teenagers, and adults along with the complete skeleton of a young woman.
The burial, dating to the 1480s, lies at the foot of the main temple in the sacred ceremonial precinct of the Aztec capital, Tenochtitlan, founded by the Aztecs in 1325. The Aztecs dominated central Mexico until falling to Spanish conquistadores in 1521.
Although several burials with multiple remains have been uncovered previously in this precinct, this is the first that includes human bones from such a wide span of ages.
The discovery offers a rare opportunity to study Aztec funerary rituals and religious beliefs. Few burials from that culture have come to light, most likely because they lie beneath modern buildings.
The burial included ten skulls—three from children and seven from adults. Archaeologists also identified small groups of ribs and femurs amid the general chaos. The loose bones appear to have come from bodies that were first buried someplace else. They were then dug up and scattered here around the single female.
Physical anthropologists are now trying to determine how many people this deposit represents, the sex and age of each one, and when they were first interred.
About 115 feet (35 meters) from the buried bones, the split trunk of an oak tree lies within a circular structure of stuccoed volcanic stones.
Archaeologists believe this may be one of the sacred trees mentioned in 16th-century Spanish descriptions of the ceremonial area. In the Aztec religion, the branches of such trees symbolically held up the sky, while their roots led to the underworld.
The wooden stakes around the tree trunk helped create a stable foundation for the structures built above them. Heavy stone platforms and temples tended to sink into the wet soil of the Aztec capital, which was situated on a marshy island in a vast lake.
The city's high water table creates a muddy excavation site.
Once the archaeologists removed the bones from the muck, they discovered possible cuts on some of the vertebrae and sternums. Such marks may be signs of human sacrifices to honor the gods. Cutting out the heart was common, but the 16th-century Spanish chronicles also depict cut throats, suffocation, burning, and shooting with arrows.
Victims included enemy warriors and members of the local community, including noble women, children offered to the rain god, albinos, dwarves, priests, prostitutes, slaves, and royal servants, killed after a king's death to accompany him to the next life.
In an artist's recreation of the Aztecs' island capital, grand temples rise in the sacred precinct behind the main market.
When Spanish conquistador Hernán Cortés arrived in 1519, Tenochtitlan — with a population that may have approached 300,000—was one of the world's ten largest cities.
The Spaniards were astounded.
"We were struck with the numbers of canoes, passing to and from the mainland, loaded with provisions and merchandise...." wrote Bernal Díaz del Castillo, a soldier who accompanied Cortés.
"The noise and bustle of the market-place below us could be heard almost a league off, and those who had been at Rome and at Constantinople said, that for convenience, regularity, and population they had never seen the like."
Illustration by P. Tom Hall, National Geographic
The City's Center, Now and Then
A translucent drawing of Tenochtitlan's main temple has been superimposed on an aerial photo from the late 1970s. In the area beneath the pyramid, the temple's buried ruins lay beneath buildings from the colonial era.
After the Spanish conquest, the newcomers tore down the Aztec city and constructed European-style buildings, which now spread across the heart of Mexico's sprawling modern capital.
Despite several centuries of transformation, the area around the main Aztec temple has retained its sacred and ceremonial character. Just beyond the excavation site stands Mexico's domed national cathedral.
Religious festivals, secular parades, and cultural events take place on the grand plaza, called the zócalo, seen here at upper left, beside the cathedral.