Perperikon
The ancient Thracian city of Perperikon is located in the Eastern Rhodopes, 15 km northeast of the present-day town of Kardzhali, Bulgaria, on a 470 m high rocky hill, which is thought to have been a sacred place. The village of Gorna Krepost ("Upper Castle") is located at the foot of the hill and the gold-bearing Perpereshka River flows near it. Perperikon is the largest megalith ensemble in the Balkans.