James Stewart

Oh yeah, essentially lasers.

LiDAR works by sending pulses of laser light out towards objects, and measuring the time it takes for the reflected laser beams to return.

And with a bit of maths, as speed is distance over time, and we know the speed of light, we can then work out the exact distance to those objects.

Over vast areas, taking lots of measurements, that means we can generate precise 3D information about Earth's surface.

And in rainforest archaeology that becomes something almost magical.

You can scan the canopy and then remove it digitally and then see the ground like the forest isn't even there and what it revealed was astounding.

Now, I should quickly say LiDAR doesn't show us ancient civilizations on its own, but it does show us shapes, microtopography, geometry, the fingerprints of organized earth moving.

Then the archeologists go in and do their bit.

They excavate, they date stuff, they test the story the terrain is telling.

But as a first step, LiDAR is like looking into your attic with X-ray vision and finding that family heirloom you thought you'd lost without opening a single box.

And in the Amazon, it did not disappoint.

In 2022, using this new airborne technology, archaeologist Heiko Pumas and his colleagues mapped settlements associated with the Casarabe culture, which thrived around AD 500 to 1400 in the Llanos de Mojos region of Bolivia.

But this wasn't just a splattering of small villages.

It was an entire system.

They had found a hierarchy, a landscape engineered for humans.

two main sites stood out from the lidar imaging data enormous in area 147 hectares and 315 hectares respectively the size of nearly 400 soccer fields the sites were embedded in a four-tier settlement system with incredibly advanced architecture including platform mounds and conical pyramid-like structures

Straight causeways ran for kilometers, and canals and reservoirs formed a water management network across the landscape.

What this was was a tropical form of urbanism, a way of living, and a city built from the rainforest itself.

And if one hidden city had finally been uncovered, then the question was unavoidable.

What else was hiding?