When it comes to underground cities, the first thing people think of is definitely the scenes from movies, or the underground castles in fairy tales, and they believe it’s impossible for underground cities to exist in reality. However, in fact, there really is an underground city in Australia called Coober Pedy, and it is also the only underground city in the world. Coober Pedy is a small town in Australia, established in 1915, when Opal gems were first discovered here, and then miners began to flock here. However, because this is the driest region in the world, with seasonal sandstorms, and summer temperatures often exceeding 40 degrees Celsius, the conditions were too harsh, so the miners dug caves in the hillsides as living spaces. Although they were just looking for a place to escape the scorching sun, they eventually established a town. The temperature inside Coober Pedy’s underground houses hovers around 24 degrees Celsius, and the air humidity is not high either, making it a summer retreat for people. In winter, the underground houses also stay warm. So, even now, with better technological conditions, people still prefer to live in underground houses. Of course, if you are interested in the underground city of Coober Pedy, you can also go there to experience it for yourself, as the tourism industry there is now quite well developed.