Gómez Chávez and his team now look forward to the next phase of the project -- exploring the last part of the tunnel and three chambers which archaeologists have seen through the robot cameras.
"The tunnel is in pristine condition, untouched for almost two millennia," said Ng "TC" Tze Chuen, an independent researcher who worked on the design of the Tláloc II-TC robot. "Can you can imagine what can be found inside?"
Ng, who helped create the Djedi robot that explored Egypt's Great Pyramid in 2010, believes the Mexican tunnel might lead to one of the most significant archaeological finds in Teotihuacan.
"The results are very encouraging indeed," he said.
According to Gómez Chávez, the tunnel was sealed twice by the Teotihuacan people. Thick walls, erected to block access, were demolished about 1,800 years ago in order to deposit something very important in the central chamber at the end of the tunnel.
"Maybe in this place," Gómez Chávez said, "we will find the remains of those who ruled Teotihuacan."