[1] It is adjacent to the geological formation of Pamukkale, meaning "cotton castle" in Turkish, famous for its travertine limestone terraces deposited by the hot springs.

There are round huts belonging to a large settlement believed to cover the side of the Çökelez Mountain overlooking the wide plain of the Lykos River.

[10] The city was expanded with the booty from the 190 BC Battle of Magnesia[citation needed] where Antiochus the Great was defeated by the Roman ally Eumenes II.

It remains unclear whether this name referred to the original temple (ἱερόν, hieron) or honoured Hiera, the wife of Telephus, son of Heracles and the Mysian princess Auge, the supposed founder of Pergamon's Attalid dynasty.

[citation needed] This name eventually changed into Hierapolis ("holy city"),[11] according to the Byzantine geographer Stephanus on account of its large number of temples.

[citation needed] New building projects were started: two Roman baths, a gymnasium, several temples, a main street with a colonnade, and a fountain at the hot spring.

After the large white limestone formations of the hot springs became famous again in the 20th century, it was turned into a tourist attraction named "Cotton Castle" (Pamukkale).

These buildings have been removed in recent years; however, the hot water pool of one hotel was retained, and (for a fee) it is possible to swim amongst ancient stone remains.

This is the monumental entrance to the Roman city and leads onto the large plateia, 14 m wide, which crosses the whole settlement, exiting a gate at the opposite side, to connect with the road that goes to Laodicea on the Lykos and then Colossae.

They are quite expressive and, while belonging to antique buildings, were evidently reused as apotropaic elements on the two sides of the gate so as to ward off evil influence.

During the reign of Septimius Severus at the beginning of the 3rd century, the old scaenae frons was replaced by a new, more monumental one, organized on three storeys and flanked by two imposing side entry buildings.

[20] The auditorium was rebuilt as well, substituting the ancient limestone seats with others in marble, and realizing a high podium on the orchestra in order to adapt the building to the organization of venationes and gladiator schools.

Several statues, reliefs (including depictions of Apollo, Dionysus, and Diana), and decorative elements have been excavated by the Italian archaeological team and can be seen in the local museum.

The back of the temple was built against the hill, the peribolos was surrounded on the remaining southern, western and northern sides, by a marble portico, which has been partially excavated.

[citation needed] Following studies carried out on site in 1998, a geologist of the Italian National Research Council recognized that the origin of both the Temple of Apollo and of the nearby Ploutonion was linked to the existence of the surface trace of a seismic fault, on which both sanctuaries were purposely built and which was revered as Gateway of Hades.

It is a small cave just large enough for one person to enter through a fenced entrance, beyond which stairs go down and from which emerges suffocating carbon dioxide gas caused by subterranean geologic activity.

Behind the 3 square metres (32 sq ft) roofed chamber is a deep cleft in the rock, through which fast-flowing hot water passes while releasing a sharp-smelling gas.

[29] During the early years of the town, castrated priests of Cybele descended into the plutonion, crawling over the floor to pockets of oxygen or holding their breath.

The stone pavement columns and other architectural remains mark a great part of the colonnaded road which ran through the city in a north–south direction.

On the north side of the city, the graves made as the 2nd and the 3rd,[clarification needed] are generally surrounded by walls and they have gardens decorated with flowers and trees (especially cypress).

)[citation needed] A raised relief on the Sarcophagus of a certain Marcus Aurelius Ammianos, a local miller, depicts the earliest known machine to incorporate a crank and connecting rod.

[36] On the pediment a waterwheel fed by a mill race is shown powering via a gear train two frame saws cutting rectangular blocks by the way of connecting rods and, through mechanical necessity, cranks (see diagram).

This is the grave of Tiberius Cladius Talamos, whose name was written in the long epigraph, and it attracts attention due to the resemblance of its facade to a home.

[40] This confusion started with a report by Polycrates of Ephesus in his Eusebius's Ecclesiastical History[41] and in his controversial letter written to Victor of Rome towards the end of the 2nd century.

[44] Fresh confirmation of his view was afforded by the discovery of an inscription at Hierapolis, showing that the church there was dedicated to the memory "of the holy and glorious apostle and theologian Philip.

In addition to these, the museum has a large section devoted to artifacts found at Beycesultan Hüyük and which includes some of the most beautiful examples of Bronze Age craft.

Among these artifacts there are statues of Tyche, Dionysus, Pan, Asklepios, Isis, Demeter and Trion which, although executed by the Romans, were inspired by the Hellenistic tradition.

These works, which were found in the excavation conducted by the British Institute of Archaeology include idols, baked earth bowls, libation cups, seals and other stone artifacts.

In other parts of the room are displayed objects from the Frigan, Hellenistic, Roman and Byzantine period such as glass cups, necklaces, gemstones (in the form of rings, bracelets, earrings and so on) and earthenware lamps.

In the works that are found in the room there are reliefs devoted to the myth of Apollo and Artemis, the delights of Dionysos and the coronation of the Roman Emperor Septimius Severus.