Pamukkale, meaning "cotton castle" in Turkish, is a natural site in Denizli province in southwestern Turkey, containing hot springs and travertines, terraces of carbonate minerals left by the flowing water. At the end of the 2nd century BC the dynasty of the Attalids, the kings of Pergamon, built the ancient city and thermal spa of Hierapolis on top of the white rock which is in total about 2,700 m long, 600 m wide and 160 m high. Its hot springs were also used for scouring and drying wool. The Romans acquired full control of it in 129 BC and it prospered under its new rulers, reaching its peak of importance in the 2nd and 3rd centuries AD. Remains of the Greco-Roman period include baths, temple ruins, a monumental arch, a nymphaeum, a necropolis and a theatre. Following the acceptance of Christianity by the emperor Constantine and his establishment of Constantinople as the ‘new Rome’ in 330 AD, the town was made a bishopric. As the place of St. Philip’s martyrdom in 80 AD, commemorated by his Martyrium building in the 5th century, Hierapolis with its several churches became an important religious center for the Eastern Roman Empire.
Tourism is and has been a major industry. People have bathed in its pools for thousands of years. As recently as the mid-20th century, hotels were built over the ruins of Hierapolis, causing considerable damage. An approach road was built from the valley over the terraces, and motor bikes were allowed to go up and down the slopes. When the area was declared a World Heritage Site, the hotels built in the 1960s were demolished and the road removed and replaced with artificial pools. Wearing shoes in the water is prohibited to protect the deposits. Access to terraces is not allowed and visitors are asked to follow the main pathway. Due to the new regulations, only small pools are allowed to be used.
In this area, there are 17 hot water springs in which the temperature ranges from 35°C to 100°C. When the water, supersaturated with calcium carbonate, reaches the surface, carbon dioxide de-gasses from it, and calcium carbonate is deposited. The depositing continues until the carbon dioxide in the water balances the carbon dioxide in the air. Calcium carbonate is deposited by the water as a soft jelly, but this eventually hardens into travertine. This reaction is affected by the weather conditions, ambient temperature and the flow duration.
Hierapolis, ‘The Sacred City’ in Greek, is an exceptional example of a Greco-Roman thermal installation established on an extraordinary natural site. The therapeutic virtues of the waters were exploited at the various thermal installations, which included immense hot basins and pools for swimming. Hydrotherapy was accompanied by religious practices, which developed in relation to local cults. The Temple of Apollo, which includes several Chtonian divinities, was erected on a geological fault from which noxious vapours escaped. The theatre, which dates from the time of Severus, is decorated with an admirable frieze depicting a ritual procession and a sacrifice to the Ephesian Artemis. The necropolis, which extends over 2 kilometres, affords a vast panorama of the funerary practices of the Greco-Roman era.
The Christian monuments of Hierapolis, erected between the 4th and the 6th centuries, constitute an outstanding example of an early Christian architectural group with a cathedral, baptistery and churches. The most important monument, situated outside the north-west wall of the city, is the Martyrium of St. Philip. At the top of a monumental stairway, the octagonal layout of the building is remarkable because of its ingenious spatial organization. According to ancient tradition, Philip the Apostle converted it and was crucified there by Domitian around the year 87. Hieropolis remained one of the two metropolises of the Phrygia Pacatiana as well as being a bishopric. The fortress, built on the cliff, testifies to its ultimate historic phase.
Beyond the city walls and meadow, in all directions there are necropolis areas. These are situated on two sides of the north way; one goes from Tripolis to Sardes and the other goes along the South way from Laodikya to Closae. Limestone and marble were used for the graves. The large necropolis is filled with sarcophagi, most famously that of Marcus Aurelius Ammianos, which bears the earliest known example of a crank and rod mechanism.
There are many architectural grave monuments in Hierapolis and they show different architectural techniques. The oldest graves are Tumulus graves of the Hellenistic period (1st and 2nd centuries BC), which are located on the east side of the foothill and were cut from the stone. These tombs belonged to rich families. Poor families' tombs were carved into the rock and are simple. On the north side of the city, the graves are generally surrounded by walls and they have gardens decorated with flowers and trees. There are also different types of grave monuments which are completely made of travertine.
The former Roman bath of the ancient city of Hierapolis has been used as the Hierapolis Archaeology Museum since 1984. In this museum, alongside historical artifacts from Hierapolis, there are also artifacts from Laodiceia, Colossae, Tripolis, Attuda and other towns of the Lycos (Çürüksu) valley. The museum’s exhibition space consists of three closed areas of the Hierapolis bath and the open areas in the eastern side which are known to have been used as the library and gymnasium. The artifacts in the open exhibition space are mostly marble and stone.