In western Turkey, about 100 miles east of Ephesus, in a valley where the Lycus River flows into the Maeander River, there once stood three important cities: Laodicea, Colosse and Hierapolis. Originally they had been Phrygian cities, but in the New Testament age they were part of the Roman Province of Asia. Hierapolis and Laodicea stood six miles apart on opposite sides of a valley with the Lycus River flowing between them. Colosse was located a few miles up river, on the same side as Laodicea.
Laodicea was the chief city of the Lycus River Valley region. The full name of the city was Laodicea ad Lyceum (Laodicea on the Lycus). Laodicea was a great center of banking and finance (Rev. 3:14-21). It was one of the wealthiest cities of the ancient world! When Laodicea was destroyed by an earthquake in 60 A.D., they refused aid from the Roman empire and rebuilt the city from their own wealth.
During the two years that Paul ministered at Ephesus, "all who dwelt in Asia heard the word of the Lord Jesus, both Jews and Greeks" (Acts 19:10). The church at Colosse was not established by Paul, and it is doubtful that he had ever visited the city (Col. 4:12-17). In Colossians 2:1 he acknowledged that many of the brethren at Colosse had never seen his "face in the flesh." It is possible that Epaphras, a fellow-worked with Paul, had established the church at Colosse. Epaphras was a "faithful minister of Christ" (Col. 1:7). Epaphras, a resident of Colosse, had great zeal for the brethren in Laodicea and Hierapolis (Col. 4:12-13).
The ruins of several well-preserved temples can still be seen in Hierapolis. The city today is known as Pamukkale ("the cotton castle" of white travertine terraces). The beautiful white cliffs around Hierapolis were formed by the calcium-oxide mixing with calcium in the hot water springs which flow to the plain of the river Maeander below. The water temperature of the spring is 95 degrees. This hot water brought about the worship of Heracles, the god of health and hot waters.
Colosse, Heirapolis and Laodicea is a free book you can download—it includes a discussion of each of these cities, and explains their importance in the New Testament age. This also has a complete bibliography and over a dozen color photographs (2nd edition; PDF file; 10 pages; 3.2MB).