The Nymph Sanctuary is situated in a picturesque area, about 600 m southeast of the village of Kasnakovo, near the city of Haskovo. This is the best preserved Thracian sanctuary in Bulgaria.

It is built on top of an ancient cult center, established around a karst mineral spring in the early-iron age. The sanctuary consists of a large complex, including many buildings and an amphitheater.

According to one of the inscriptions, which is still preserved, the sanctuary was built by a Thracian veteran from the Roman army and his wife in honour of the water nymphs and Aphrodite. The three minerals springs here are shaped architecturally. Local residents thinks the waters of the springs have healing power.

The sanctuary has been officially declared a monument of culture of national significance in 1968.