8 million 180 million 1.8 million 80 million
Serbia Macedonia Greece Turkey Greece Macedonia Romania Russian Federation
Russian Ottoman Mongol British
Plovdiv Sofia Rousse Burgus
Baltic Sea Caspian Sea Mediterranean Sea Black Sea
Struma River Danube River Iskar River Maritsa River
Rhodope Mountains Pyrenees Mountains Balkan Mountains Caucasus Mountains
Backhoro Monastery Aladzha Monastery Rila Monastery Troyan Monastery
Romania Turkey Serbia Greece