Atanas () is a fortress in Serbia. It is located 8 km southeast from Pirot, near the village Krupac. It was an ancient settlement in the area in the 6th century BC. Today remains of the keep can be seen.Aleksandar Deroko, „Средњевековни градови у Србији, Црној Гори и Македонији“, Belgrade, 1950
See also List of fortifications in Serbia
References