The town is called Coober Peddy, and is located in the Outback in Australia. The area’s claim to fame is the series of old Opal mines, which make up tunnels that not only can be toured, but can also be lived in!
From Wikipedia: The harsh summer desert temperatures mean that many residents prefer to live in caves bored into the hillsides. A standard three-bedroom cave home with lounge, kitchen, and bathroom can be excavated out of the rock in the hillside for a similar price to a house on the surface. It remains at a constant temperature, whereas surface living needs air-conditioning, especially during the summer months, when temperatures often exceed 40 degrees Celsius (104 degrees Fahrenheit).
The local golf course – mostly played at night with glowing balls, to avoid daytime temperatures – is completely free of grass and golfers take a small piece of “turf” around to use for teeing off.
Inside these opal mines can not only be found comfortable housing, but bookstores, churches, and a Comfort Inn as well!