Hierapolis was an ancient Greek city located on hot springs in classical Phrygia in southwestern Anatolia. Its ruins are adjacent to modern Pamukkale in Turkey and currently comprise an archaeological museum designated as a UNESCO World Heritage Site. The site has the Tomb of Philip the Apostle. The hot springs have been used as a spa since the 2nd century BC, with many patrons retiring or dying there. The large necropolis is filled with sarcophagi, most famously that of Marcus Aurelius Ammianos, which bears a relief depicting the earliest known example of a crank and rod mechanism. The great baths were constructed with huge stone blocks without the use of cement and consisted of various closed or open sections linked together. There are deep niches in the inner section,[clarification needed] including the bath, library, and gymnasium. What We See Here: (150 Minutes) • Travertines (45 minutes) • Hieropolis Archaeology Museum (15 minutes) • Hieropolis Ancient Pool (30 minutes) • Ancient Theater (30 minutes) • Temple of Apollo (10 minutes) • Streets and Gates (20 minutes)

Pamukkale, meaning "cotton castle" in Turkish, is a natural site in Denizli in southwestern Turkey. The area is famous for a carbonate mineral left by the flowing water. It is located in Turkey's Inner Aegean region, in the River Menderes valley, which has a temperate climate for most of the year. The ancient Greco-Roman city of Hierapolis was built on top of the white "castle" which is in total about 2,700 metres long, 600 m wide and 160 m high. It can be seen from the hills on the opposite side of the valley in the town of Denizli, 20 km away. Known as Pamukkale (Cotton Castle) or ancient Hierapolis (Holy City), this area has been drawing the weary to its thermal springs since the time of Classical antiquity. The Turkish name refers to the surface of the shimmering, snow-white limestone, shaped over millennia by calcium-rich springs. Dripping slowly down the vast mountainside, mineral-rich waters foam and collect in terraces, spilling over cascades of stalactites into milky pools below. Legend has it that the formations are solidified cotton (the area's principal crop) that giants left out to dry.