BBC:
“I was on something like page 16 of Google search and found a laser survey done by a Mexican organisation for environmental monitoring,” explains Luke Auld-Thomas, a PhD student at Tulane university in the US.
It was a Lidar survey, a remote sensing technique which fires thousands of laser pulses from a plane and maps objects below using the time the signal takes to return.
But when Mr Auld-Thomas processed the data with methods used by archaeologists, he saw what others had missed - a huge ancient city which may have been home to 30-50,000 people at its peak from 750 to 850 AD.
the team’s findings show just how many undiscovered treasures the area could yet yield.
“We didn’t just find rural areas and smaller settlements,” he said. “We also found a large city with pyramids right next to the area’s only highway, near a town where people have been actively farming among the ruins for years. The government never knew about it, the scientific community never knew about it. That really puts an exclamation point behind the statement that no, we have not found everything, and yes, there’s a lot more to be discovered.”