The tomb-cult complex "Ostrusha" functioned as a temple of the Thracian god of immortality Sabazius 800 years - from IV century B.C till IV century A.D. With its architecture and frescoes the tomb is among the most remarkable achievements in Thrace and the Valley of the Thracian Kings.
The tomb of Seuthes III in the mound of "Golyama Kosmatka" is important evidence of the Thracian Orphic rites not only at national level, but also worldwide. The magnificent golden wreath of the ruler, golden kylix, knee pads, helmet with plastic ornaments and others were found in it. The bronze head from the statue of Seuthes III, ritually buried in front of the facade is remarkable, unusually inspired and detailed. And at the bottom of Koprinka dam the ruins of his capital Sevtopolis are buried. Studied and described in details, the town is shown in the halls of the Museum. Sredna Gora and the village of Buzovgrad are near the dam, where the most ancient shrine of the Valley is discovered.