Mexican archeologists using ground-penetrating radar have detected underground chambers they believe contain the remains of Emperor Ahuizotl, who ruled the Aztecs when Columbus landed in the New World. It would be the first tomb of an Aztec ruler ever found.
The find could provide an extraordinary window into Aztec civilization at its apogee. Ahuizotl, an empire-builder who extended the Aztecs' reach as far as Guatemala, was the last emperor to complete his rule before the Spanish Conquest.
Accounts written by Spanish priests suggest the area was used by the Aztecs to cremate and bury their rulers. But no tomb of an Aztec ruler has ever been found, in part because the Spanish conquerors built their own city atop the Aztec's ceremonial center, leaving behind colonial structures too historically valuable to remove for excavations.
One of those colonial buildings was so damaged in a 1985 earthquake that it had to be torn down, eventually giving experts their first chance to examine the site off Mexico City's Zocalo Plaza, between the Metropolitan Cathedral and the ruins of the Templo Mayor pyramid.
Archeologists said they have located what appears to be a 2m-by-2m entryway into the tomb about 4m below ground. The passage is filled with water, rocks and mud, forcing workers to dig delicately while suspended from slings. Pumps work to keep the water level down.
"We are doing it very, very slowly ... because the responsibility is very great and we want to register everything," said Leonardo Lopez Lujan, the lead government archeologist on the project.
"It's a totally new situation for us, and we don't know exactly what it will be like down there," he said.
As early as this fall, they hope to enter the inner chambers -- a damp, low-ceilinged space -- and discover the ashes of Ahuizotl, who was likely cremated on a funeral pyre in 1502.
By that time, Columbus had already landed in the New World. But the Aztecs' first contact with Europeans came 17 years later, in 1519, when Hernan Cortes and his band of conquistadors marched into the Mexico Valley and took Ahuizotl's successor hostage, his nephew Montezuma.
Ahuizotl's son Cuauhtemoc took over from Montezuma and led the last resistance to the Spaniards in the battle for Mexico City in 1521. He was later taken prisoner and killed. Like Montezuma, his burial place is unknown.
Because no Aztec royal tomb has ever been found, the archeologists are literally digging into the unknown. Radar indicates the tomb has up to four chambers, and scientists think they will find a constellation of elaborate offerings to the gods on the floor.
"He must have been buried with solemn ceremony and rich offerings, like vases, ornaments ... and certainly some objects he personally used," said Luis Alberto Martos, director of archeological studies at Mexico's National Institute of Anthropology and History.
The tomb's curse -- water -- may also be its blessing. Lopez Lujan said the constant temperature of the pH-neutral water in the flooded chambers, together with the lack of oxygen, discourages decomposition of materials like wood and bone that have been found at other digs around the pyramid, which was all but destroyed in the Conquest.
`This would be quite an important find for Aztec archeology,'' said Michael Smith, an archeologist at Arizona State University who is not connected to the dig. ``It would be tremendously important because it would be direct information about kingship, burial and the empire that is difficult to come by otherwise.''