The hot springs at Hierapolis caused the city to be known for its textile industry. There were guilds of wool workers, carpet weavers, and purple dyers. The hot medicinal springs (95°) attracted visitors. The city prospered under the Romans, but often suffered from earthquakes.
Recall that Hierapolis is one of three cities of the Lycus River valley named in the New Testament.
For I can testify that [Epaphras] has worked hard for you and for those in Laodicea and Hierapolis. (Colossians 4:13 NET)