Scientists think this strange underground labyrinth could be just the place for Martian bases.

Mars is not a hospitable planet, so finding the right place for a future human settlement will be crucial.

One potential candidate, recently imaged by the Mars Reconnaissance Orbiter (MRO), could be “skylights” leading to immense, underground lava tubes.

These mysterious holes could provide many benefits—including protection from radiation and wild planetary temperature swings—and could even be home to microbial life.

While scientists are unsure exactly what this hole could be, its presence in the Tharsis Montes region—a bulge of ancient volcanism that houses some of the planet’s largest volcanoes along the equator of the western hemisphere—could mean than the hole is an entrance or “skylight” to an underground labyrinth of lava tubes. A formation like that could be a huge opportunity for searching for microbial life but also as a potential Martian home for humans.

Because Mars can’t ward off radiation with a magnetic field, creating a base in these kinds of tubes could help protect future astronauts from radiation levels that are some 40 to 50 times greater than those experienced on Earth. These pits could also help create a stable environment that’s protected from Mars’ incredible temperature swings. After all, a summer day along the Martian equator can reach temperatures as high as 70° Fahrenheit, while a summer night can plummet to about -100° Fahrenheit.