Situation of the three cities.
Lying in, or overhanging, the valley of the Lycus, a tributary of the Mæander, were three neighbouring towns, Laodicea, Hierapolis, and Colossæ[[1]]. The river flows, roughly speaking, from east to west; but at this point, which is some few miles above its junction with the Mæander, its direction is more nearly from south-east to north-west[[2]]. Laodicea and Hierapolis stand face to face, being situated respectively on the southern and northern sides of the valley, at a distance of six miles[[3]], and within sight of each other, the river lying in the open plain between the two. The site of Colossæ is somewhat higher up the stream, at a distance of perhaps ten or twelve miles[[4]] from the point where the road between Laodicea and Hierapolis crosses the Lycus. Unlike Laodicea and Hierapolis, which overhang the valley on opposite sides, Colossæ stands immediately on the river-bank, the two parts of the town being divided by the stream. The three cities lie so near to each other, that it would be quite possible to visit them all in the course of a single day.
Their neighbourhood and intercourse.
Thus situated, they would necessarily hold constant intercourse with each other. We are not surprised therefore to find them so closely connected in the earliest ages of Christianity. It was the consequence of their position that they owed their knowledge of the Gospel to the same evangelist, that the same phases of thought prevailed in them, and that they were exposed to the same temptations, moral as well as intellectual.
Physical forces at work.
The physical features of the neighbourhood are very striking. Two potent forces of nature are actively at work to change the face of the country, the one destroying old land-marks, the other creating fresh ground.
Frequent earthquakes.
On the one hand, the valley of the Lycus was and is especially liable to violent earthquakes. The same danger indeed extends over large portions of Asia Minor, but this district is singled out by ancient writers[[5]] (and the testimony of modern travellers confirms the statement[[6]]), as the chief theatre of these catastrophes. Not once or twice only in the history of Laodicea do we read of such visitations laying waste the city itself or some flourishing town in the neighbourhood[[7]]. Though the exterior surface of the earth shows no traces of recent volcanoes, still the cavernous nature of the soil and the hot springs and mephitic vapours abounding here indicate the presence of those subterranean fires, which from time to time have manifested themselves in this work of destruction.
Deposits of travertine.
But, while the crust of the earth is constantly broken up by these forces from beneath, another agency is actively employed above ground in laying a new surface. If fire has its fitful outbursts of devastation, water is only less powerful in its gradual work of reconstruction. The lateral streams which swell the waters of the Lycus are thickly impregnated with calcareous matter, which they deposit in their course. The travertine formations of this valley are among the most remarkable in the world, surpassing even the striking phenomena of Tivoli and Clermont[[8]]. Ancient monuments are buried, fertile lands overlaid, river-beds choked up and streams diverted, fantastic grottos and cascades and archways of stone formed, by this strange capricious power, at once destructive and creative, working silently and relentlessly through long ages. Fatal to vegetation, these incrustations spread like a stony shroud over the ground. Gleaming like glaciers on the hill-side they attract the eye of the traveller at a distance of twenty miles[[9]], and form a singularly striking feature in scenery of more than common beauty and impressiveness.