Tourists enjoy themselves in an ancient pool of Hierapolis in Turkey on June 16, 2013. Hierapolis was an ancient city located on hot springs in classical Phrygia in southwestern Anatolia. The hot springs have been used as a spa since the 2nd century B.C., with many patrons retiring or dying there. The Hellenistic city was built on a grid with streets running parallel or perpendicular to the main thoroughfare. Its ruins comprise an archaeological museum designated as a UNESCO World Heritage Site. (Xinhua/Lu Zhe)