There are ancient myths about lost cities in Central America, and from time to time adventurous people with lots of money have set out to find them. The lure of possible treasure is strong, but mostly it’s the desire to discover what those before them have not been able to. To uncover a history that has been lost and become myth. Once of these attempts, started in 2012, has paid off. They found a lost city somewhere in the rain forest in Honduras, and this year they’ve begun to excavate it, coming up with the first artifacts from a lost civilization.

The technology they used to find the city is called LIDAR. It’s like radar, but it uses visible light LASERS instead of radio waves (the initial RA in RADAR stands for radio waves, which are just like light except lower energy).   First, the team used satellite photos to identify a valley that looked like a reasonably likely place for an ancient city. Then they flew a plane low and slow over the area. The plane continuously shot lasers at the ground below and sensed when the lasers came back to the plane after bouncing off of what was below. If the rays came back quickly, they had bounced off the top of the trees. The ones that took the longest to come back must have bounced off of the ground below.

This is a rainforest we’re talking about. When human look down from the plane, it’s all treetops. There’s no structure to it at all. The researchers estimated that the lasers from the plane only hit the ground about 5% of the time – the rest of the time they bounced off trees. 95% is pretty good coverage. But that last 5% was enough for the researchers to identify what they were looking for. They subtracted from the image all the information that came from the trees and their varied heights. It was like virtually deforesting the rain forest so they could see what was underneath. And in one location, over one to two square miles, they could see grids of raised dirt, indicating a buried city with buildings and streets. The signature of man-made civilization.

From my point of view, that’s what the exciting part of this is. Here’s all the data, peel back what you don’t want, and there’s a new civilization. But that doesn’t count as a discovery for archeologists; they need ground-truthing. So then a small army of pitiable researchers went slogging through the jungle with machetes to find these hidden mounds. Did I mention that this is in a region known as the Mosquitia rain forest?

They found them. They published some of their first findings in March 2015, and we should see much more from them in the coming year. One of the first things they found was some sort of ritual cache including a mask they’re calling a were-jaguar mask (a distant cousin of werewolves, I suppose). The civilization dates, they estimate, from around 1000-1400 C.E., but it doesn’t appear to be Mayan – it’s something else they have yet to name. This is an awesome way to use new technology to discover ancient treasure troves.

The rain forest isn’t the only place where LIDAR is useful. Closer to home, it’s being used to unearth abandoned structures in New England. When Europeans first came to America, they set up farms and farming towns, but over the next 100-200 years, they figured out that New England soil wasn’t very good for farming and the soil out west was much better, so many farms were abandoned as farmers headed west. LIDAR is being used to find those farms and their structures that are now covered with New England deciduous forest.

LIDAR allows us to see structure that we can’t glimpse with our own eyes by allowing us to subtract the vast majority of visual information and see the underlying ground. I’m excited to see what else we’ll be able to find with it.