Russia, Republic of Tatarstan. Bolgar Historical and Archaeological Complex. Bolghar was intermittently capital of Volga Bulgaria from the 8th to the 15th centuries, along with Bilyar and Nur-Suvar. It was situated on the bank of the Volga River, about 30 km downstream from its confluence with the Kama River. West of it lies a small modern town, since 1991 known as Bolgar. The UNESCO World Heritage Committee declared ancient Bolghar hill fort as a World Heritage Site in 2014. White Mosque.