Bulgaria shares borders with Serbia , Macedonia , Romania , Greece , and Turkey . Two mountain ranges and two great valleys mark the topography of Bulgaria , a country the size of Tennessee and situated on the Black Sea . The Maritsa is Bulgaria 's principal river, and the Danube also flows through the country.

Sofia is the capital city of Bulgaria . Important cities are Plovdiv , Varna , Bourgas, Rousse, Stara Zagora , Pleven , Dobrich, Sliven and Shumen .

Bulgaria 's climate is temperate with cold snowy winters and hot summers.

Bulgaria is mountainous with over four thousand mapped caves. Thirty-eight percent of Bulgaria consists of forests and woodlands; there are many rivers, waterfalls, lakes and mineral springs.

Bulgaria 's population was estimated at 7,385,367 in 2006.
Bulgarian is the official language.

The main religion in Bulgaria is Bulgarian Orthodox. Around twelve percent of the people are Muslim.

One of Bulgaria 's largest lakes is Smradlivoto in the Rila Mountains .

Raiskoto Praskalo Waterfall, known as the "Heaven Spray", is Bulgaria 's highest waterfall.

Bulgaria is named after the Bulgar people who arrived in the country in the late seventh century.

The Thracian Serdi tribe settled in Sofia in the seventh century BC. The name of Bulgaria 's capital city, Sofia , comes from the name "Serdica".

The official currency is the Lev (plural; Leva) divided into 100 Stotinki.