Built between the 4th and 6th Centuries, statues, remains of the city, cathedral, baths and churches represent a select example of Early Christianity architectural category in Hierapolis. Imposing white travertines, created by waters, which come from the southern foothills of Cal Mountain and contain calcium oxide has created a striking view in Pamukkale. White travertine terraces, which have been mostly unspoiled and whose appearance have been preserved, hot water pools, formed among thousands of antique columns and marble decorative elements, are integrated and intermingled in Hierapolis (Holy City) ancient city.
Travertines are rocks, which have formed through sedimentation as a result of chemical reaction, due to multi-directional, various reasons and environments. Sedimentation is in the form of gel in the first stage. Weather conditions, heat loss, spread and duration of flow have an impact on the formation of whiteness. Sedimentation continues until the carbon dioxide in the thermal water equilibrates with the carbon dioxide in the air. Waters, which come out from the sources, can whiten up to 4.9 m2 area up to 1 mm thickness.
Hierapolis Ancient City has been inhabited for at least 10 thousand years. Written date of the region is recorded as 190 B.C. The reason the city was founded in this region is the healing thermal water. It is approximately 20 km to the north of Denizli. The ancient city is among a few historic areas. According to ancient geographers Strabo and Ptolemy, Hierapolis was very near Laodicea at the border of Kao and Tripolis. Therefore, it was a Phyrigian city. It is thought that the city was founded by Pergamene King Eumenes II and received its name from Heira, wife of the founder of Pergamum.
What formed the appearance of the ancient pool, as seen today, is the earthquake, which took place in the 7th Century A.D. The ionic portico (1st Century A.D.) belonging to the public agora, which is situated by the colonnaded street, collapsed into the pool, which was formed inside the fault, which was created due to the earthquake. The city became an important medical center, thanks to its thermal springs and patients, who come from many parts of Anatolia to get well stayed there until the end of their lives here during the Roman period. Roman Necropolis consists mostly of the tombs of these patients and has cultural variety. Nymphaeum (Ancient Fountain Structure) in Hierapolis and the Roman Baths were built due to this characteristic of the city and these buildings survived to the present day. Northern gate, included in the city wall system in the city of Hierapolis dates back to the end of the 4th Century A.D and the Northern Gate comprised the monumental entrance symmetrically to the Southern Gate in the Byzantine Era. The lion, standing apotropaically to protect the ancient city from bad effects, panther, gorgon’s head and four decorated consoles, which had probably been used in an older building, survived to the present day on both sides of the entrance.