Pleven, Plevna - the town was taken from the Turks by the Russians in 1877 after a siege of 143 days

NATO, North Atlantic Treaty Organization - an international organization created in 1949 by the North Atlantic Treaty for purposes of collective security

Balkan country, Balkan nation, Balkan state - a country on the Balkan Peninsula

Bulgarian capital, Serdica, Sofia - capital and largest city of Bulgaria located in western Bulgaria

Philippopolis, Plovdiv - an ancient city in southern Bulgaria; commercial center of an agricultural region

Danube, Danube River - the 2nd longest European river; flows into the Black Sea

Europe - the 2nd smallest continent (actually a vast peninsula of Eurasia); the British use `Europe' to refer to all of the continent except the British Isles

Bulgarian - a native or inhabitant of Bulgaria