April 28, 2013 -- Mexican archeologists discovered three previously unknown chambers under a pyramid in Teotihuacan, an ancient city 31 miles northeast of Mexico City, thanks to a remote-controlled robot that crawled into the pyramid's underbelly.
Click here to see the robot in action (in Spanish).
This is the second time a robot has been used for archaeological exploration in Mexico. The technology has been used at other ancient sites, too: a similar device was used in Egypt 10 years ago to explore the Cheops pyramid.
This robotic expedition is particularly significant because it will allow researchers to better delineate the ancient Mesoamerican city's social structure, which is still not well understood.
Archeologist Sergio Gómez Chávez, director of the "Tlalocan Project: Underground Road" with the National Institute of Anthropology and History, hypothesizes that the three chambers contain remains of high-ranking members of the ancient society. A major indication of this is that the pyramid where the chambers were found, called the Quetzalcoatl pyramid, is thought to have been the city's center of government.
The chambers were discovered at the end of a tunnel that was last accessed by humans 1,800 years ago when the entrance was blocked by Teotihuacans. The tunnel was discovered in 2003, but its exploration required years of planning until they could find the right technology to reach it. Due to the amount of debris blocking the tunnel, it's not yet accessible by humans.
Teotihuacan is one of the oldest known archaeological sites in Mexico. The city reached its peak between 250 and 500 A.D. when it had a population close to 150,000 residents. It collapsed around the 7th century, and was later used by the Aztecs when they arrived in the city in the 14th century.
The remote-controlled vehicle that will enter the tunnel is called Tlaloc II, after the Aztec god of rain. It's a small 4x4 vehicle, fitted with a scanner that takes measurements, and a video camera that relays images to researchers above ground.