The Sassi of Matera represent one of the oldest still existing settlements in Europe, going back to 7000 BC when troglodyte dwellers dug caves into the calcareous sandstones prevailing in that area. Throughout much of the 20th century the Sassi were an area of poverty where people, in principle, still lived in the same caves as thousands of years earlier. Declared a UNESCO World Heritage in 1993, the site has become quite touristy.