The Australian town of Coober Pedy looks like something straight out of a movie—probably because it is. In 1985, Mel Gibson, Tina Turner and a team of filmmakers descended onto this barren mining town in the South Australian Outback to shoot Mad Max Beyond Thunderdome. The otherworldly landscape, which is checkered with ruddy-colored mounds of sandstone—the result of years of opal mining—was the perfect backdrop for the post-apocalyptic movie. That very landscape, not to mention the lure of finding a pricey opal, has drawn people here for years. It’s also forced the town’s residents underground—literally.

“People come here to see things differently,” Robert Coro, managing director of the Desert Cave Hotel in Coober Pedy, tells Smithsonian.com. Parts of his hotel are located below the ground, like many other buildings in town. “It’s that kind of adventure mentality that attracts people here in the first place.”

Nothing about Coober Pedy is for the faint of heart. For starters, it’s hot—really hot. In the summer temperatures can creep up to 113 degrees in the shade, assuming you can find a tree large enough to stand under. Before the city passed a tree-planting initiative encouraging residents to plant seeds around town, its tallest tree was a sculpture built from scraps of metal. Even grass is considered a commodity in Coober Pedy, where the local (dirt) golf course provides golfers with squares of carpet for their tees.

Since its founding 100 years ago after a teenager discovered opal gemstones there, the town has been ground zero for opal mining. An estimated 70 percent of the world’s opal production can be linked back to the town, earning it the title of Opal Capital of the World, and the majority of its 3,500 residents work in the opal industry. One of the latest finds was a set of opalized pearls dating back more than 65 million years—but the city offers other kinds of buried treasure, too.