Underground dwellings in Tunisian town of Matmata. On the slope of a hill the cave village of Matm,ta is located. At this place the Berber people dig their homes out of the ground for more than 1000 years. There are more than 100 underground houses. It is very useful to build subterranean homes in hot arid climates. Underground, the temperature is always the same. At night when the desert is very cold, it is comfortably warm in the cave, and at day when the sun burns down, the caves are cool. The houses are built around artificial craters, 5 to 10 meters deep, with doors and windows in the steep walls towards the crater. Those craters look like a patio or a Roman atrium, and the lower part of the walls is often painted white. Sometimes several of those craters are connected by a labyrinth of tunnels. But most of the houses are a single crater with several rooms around, used for living, sleeping or stooring food. Matmata, Tunisia, North Africa.