Particularly interesting are the remains of an aqueduct starting several km away at the Baspinar spring in Denizli, and possibly having another more distant source. Unusually, to cross the valley to the south of Laodicea, instead of the usual open channel carried above the level of the city on lofty arches as was the usual practice of the Romans, an inverted siphon was employed consisting of a double pressurised pipeline, descending into the valley and back up to the city. The water pressure in the siphon at the bottom of the valley was a challenge in the absence of strong piping. The low arches supporting the siphon commence near the summit of a low hill to the south of the city where the header tank was located, and thence continue to the first terminal distribution tank (castellum aquae) at the edge of the hill of the city, whose remains are visible to the east of the stadium and South Baths complex. The water was heavily charged with calcareous matter, as several of the arches are covered with a thick encrustation where leaks occurred at later times. The siphon consisted of large carved stone pipes; some of these also are much incrusted, and some completely choked up. The terminal tank has many clay pipes of various diameters for water distribution on the north, east and south sides which, because of the choking by sinter, were replaced in time. To the west of the terminal is a small fountain next to the vaulted gate. The aqueduct appears to have been destroyed by an earthquake, as the remaining arches lean bodily on one side, without being much broken. A second distribution terminal and sedimentation tank is visible 400 m north of the first, to which it was connected via another siphon of travertine blocks, and this one is bigger and supplied most of the city.