Only 10 km south from Sozopolis the reserve Ropotamo is located. The area along the flow of Ropotamo river was declared a reserve in 1940. It is known for its virgin nature, its variegated relief, cliff beaches, large sand strip, sand dunes, longose forests and swamps near the sea. The rriver is named after the Greek goddess Ro (Ro in Greek means "to run” and “potamo” means “river”), who, with her songs and beauty has won the mercy of the pirates, who terrorised ancient Apolonia. The region was populated in the early Iron age XІ – X B.C. and later here came Thracians, Greeks, Romans, Slavs and Proto-Bulgarians. Since then there are remnants of the fortresses Burhama, Valchanovo cale, Dolmenite, the ancient ports along the mouth of Ropotamo river. You can also visit the sacrificial stones Apostol Tash, Beglik Tash and the Saint Paraskeva church.
There are lots of natural objects there – the estuary of Ropotamo river, the Arkutino swamp, longose forests, rock phenomena, wet lands, swamps and many other. The estuary of Ropotamo river is one of the main tourist landmarks in the reserve. Within the boundaries of the reserve 257 species of birds can be traced, out of which 71 are recorded in the Red Book of Bulgaria.
The reserve is a habitat of rare animal species. The reserve is inhabited by 50 types of mammals: noble deer and lopatar – deer, roes, muflons, foxes, jackals, otters and colonies of bats live in the rock caves. The extinct species of mammals are the bear, the lynx and the monk seal.
The unique Thracian sanctuary Beglik Tash was discovered in 2003, only 30 km south from Sozopol. It was defined as the earliest, found so far, Thracian megalith sanctuary in South-Eastern Thrace along the Black Sea coast. Researches prove that since the end of the Bronze age (XIII B. C.) here thrived active human activity. The materials found prove that the sanctuary was mostly visited by Thracians. In its essence the location served similar functions as monasteries have nowadays.
It is basically connected with the cult to fertility, the Goddess - Mother and the Orphic dedication and immortalisation of Heroya. The gifts of semi-precious stones testify this theory. No animal traces were found in the very well preserved sacrificial altar, only vegetative - only plants have been sacrificed instead.
The sanctuary consists of 1 central part and 2 circles of smaller structures around it, with total area of the sanctuary around 6000 sq. m. It is a circle of large boulders, placed on rocky surface in the middle of a green field. The stones which were brought there by humans are arranged in a unique manner, forming a clock, calendar and an observatory. For this Beglik Tash is famous as Bulgarian Stonehenge. The large boulders are partially processed by human hand and mounted there, and the stone slabs are arranged in unique shapes. In the flat cliffs stone circles, bathing pools and "mark steps" are cleft. The residential buildings and the cult fireplaces complement the evidences for human activity there.
The legend says that Yason and the Argonauts have passed through the sanctuary as to consult the prophets and to grant gifts to Gods before setting off on their journey in seeking the Golden Fleece.
Now the archaeologists "reign" the ancient sanctuary and they still have to interpret its secrets.