As a child, my favorite activity at the beach was digging through the sand for lost objects. Old coins, keys, painted shells and tarnished rings lined the pockets of my beach shorts after a day by the sea. But what if there were an easier way to look at buried treasure, a way without having to get my palms dirty and sand under my fingernails?

In the world of archaeology, there is. It’s called lidar. Short for “light detection and ranging,” lidar is a remote sensing device attached to the bottom of a helicopter or airplane that sends measured laser pulses toward Earth. The light bounces off the Earth’s surface and back to the lidar device with measurements and outlines of the ground below. This information is then compiled to form precise, three-dimensional maps.

What makes lidar so special is that it can reveal objects hidden beneath both vegetation and water and, by doing so, unearth buried artifacts, dwellings and—in this particular case—entire hidden cities.

Let’s take a trip to Cambodia in Southeast Asia, where scientists and archaeologists recently used lidar to uncover a massive residential city surrounding Angkor Wat, a Hindu (and, later, Buddhist) temple built in the twelfth century during the Khmer Empire. Considered one of the world’s largest religious sites and Cambodia’s most popular tourist destination, the temple has been visited by millions of tourists each year, none of whom had any idea just what kind of buried treasure lay around them.

Archaeologist Damian Evans of Cambodia’s Siem Reap Center and his team spent nearly two weeks using lidar to survey the area around Angkor Wat—a vast expanse of thick jungle vegetation—in search of artifacts. Imagine their astonishment when they discovered a massive “buried” city with the temple at its center, complete with residential districts, dried-up canals and ponds, streets, and buildings!

One of the more mystifying discoveries was a series of lines in the ground in the shape of labyrinthine coils. Evans and the team could not be sure what these coils were used for and claimed that there was nothing similar to these coils in surviving Hindu writings or art. Overall, the discovery of the city surrounding Angkor Wat provides exciting new clues for learning more about the ancient Khmer people.

So next time you’re at the beach, dig your hands a little deeper into the sand. You never know—you might just discover an ancient city.

Did You Know?

Lidar can also be used to take “photographs” of living beings, creating surreal pieces of art. Photographers discovered this unique feature in 2014 while profiling the landmarks and people of Harari, Ethiopia. They found that using the lidar could blur and smudge images of people, generating visually-stunning photographs. The artwork was displayed in an exhibit at the New York Institute of Technology in 2014.