Year 2003, a sanctuary of a very old town was found near Primorsko. This is an ancient observatory, called Beglick Tash, which represents a peculiar calendar. It stands for the cult of the Goddes-Mother, the Sun and the mythical Tracian tzar Orpheus. Beglick Tash was built in XXIV century B.C. and was used till IV century A.C. According to historical researches of Tracian mythology, the region of Primorsko was worshipped as The Sacred Mountain. All around the coastal line there are remains of great ancient towns. The walls of one of the largest and most powerful towns - Ranuli - can still be seen on "Valchanova fortress" hill. Nowadays, the area surrounded by its walls, is around 30 dka. According to the historians, this is one of the biggest stronghold-cities in Bulgaria, dating back to the Middle Ages. Later on, the village settled on that place was called Chenger, and afterward Kjupria. Today, this is the town of Primorsko.