If people were to start living on the moon, where might they build their homes?

According to a theoretical study, large volcanic tunnels, referred to as “sinuous rilles,” are structurally stable enough to one day house cities on the moon.

The tubes are a result of volcanic eruptions, which create “pipe-like crust” as lava cools around a flowing stream. Once the flow stops, large hollow tunnels are left behind, which can one day provide future space explorers shelter from things like cosmic radiation and meteorite impacts.

Researchers at Purdue University are currently examining whether these large channels exist on the moon’s surface, and if they can remain structurally sound.