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Mini-robot finds surprise in Mexico's ancient Temple of Quetzalcoatl

Researchers lowered a robot with a camera into a tunnel under Mexico's Teotihuacan and have discovered three ancient chambers under the pyramid. NBCNews.com's Dara Brown reports.

A diminutive robot helped researchers make a substantial discovery during preliminary tests conducted in a tunnel running under the Temple of Quetzalcoatl at the archaeological site of Teotihuacan, the team said Monday.

The team expected to find only one chamber in the last section of the tunnel — but instead, they found three, team leader Sergio Gomez said in a report published by the Mexican newspaper El Universal. The chambers are thought to have been used by Teotihuacan's rulers roughly 2,000 years ago for royal ceremonies or burials, but they're so choked with mud and rubble that they haven't been explored in modern times.

Henry Romero / Reuters

A worker from the National Institute of Anthropology and History walks next to a robot used to explore ruins at the entrance of a tunnel in the archaeological area of the Quetzalcoatl Temple, near the Pyramid of the Sun at the Teotihuacan archaeological site.

That's where the 3-foot-long (1-meter-long) robot known as Tlaloc II-TC comes in: The robot is designed to drive through the tight spaces leading to the back of the tunnel beneath the Temple of Quetzalcoatl, also known as the Temple of the Feathered Serpent. It's equipped with a video camera as well as mechanical arms to clear obstacles.

The current project follows up on an earlier round of robotic exploration by Tlaloc II-TC's predecessor, Tlaloc I, in 2010. (Tlaloc was the Aztec god of rain.)

In 2010, Gomez said there was a "high possibility that in this place, in the central chamber, we can find the remains of those who ruled Teotihuacan." The city was once an influential center of Mesoamerican culture, but little is known about its rulers. Archaeologists have not yet found any depictions of a ruler, or any tomb of a monarch.

El Universal quoted Gomez as saying that the configuration of the space beneath the temple appears to be similar to that of the tunnel running beneath Teotihuacan's Pyramid of the Sun, where four chambers were explored in the 1970s. About 76 meters (250 feet) of the Quetzalcoatl tunnel have already been uncovered, leaving 30 meters (100 feet) or so in the last section. After a round of robotic reconnaissance, archaeologists intend to clear out that section for exploration.

Henry Romero / Reuters

Visitors look on at the archaeological area of the Temple of Quetzalcoatl, near the Pyramid of the Sun at the Teotihuacan archaeological site, about 60 kilometesr (37 miles) north of Mexico City.

Henry Romero / Reuters

Archaeologist Sergio Gomez from the National Institute of Anthropology and History speaks to the media during a news conference in the archaeological area of the Temple of Quetzalcoatl on Monday. A remote-controlled robot has relayed back video images of what appears to be three ancient chambers beneath the temple.

From Aug. 4, 2010: A tunnel is discovered beneath temple ruins in Teotihuacan, Mexico, that experts believe lead to tombs and an underground city dating back to 100 B.C. TODAY.com's Dara Brown reports.

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Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.