Bulgaria officially the Republic of Bulgaria is a parliamentary republic in Southeast Europe. It borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east. With a territory of 110,994 square kilometers (42,855 sq mi), Bulgaria ranks as the 15th-largest country in Europe.

Prehistoric cultures began developing on Bulgarian lands during the Neolithic period. Its ancient history has been marked by the presence of the Thracians, and later by the Greeks and Romans. The emergence of a unified Bulgarian ethnicity and state dates back to the seventh century and the First Bulgarian Empire, which functioned as a cultural hub for Slavic peoples and spread over most of the Balkans during the Middle Ages. With the downfall of the Second Bulgarian Empire in 1396, its territories came under Ottoman rule for nearly five hundred years. The Russo-Turkish War of 1877–1878 resulted in the Third Bulgarian State, recognized in 1908. Shortly afterwards, Bulgaria engaged in a series of major conflicts with its neighbors and allied with Germany in both World Wars. In 1946 it became people's republic and it was a part of the Warsaw Pact until 1989, when the Communist Party allowed multi-party elections. After 1990 Bulgaria transitioned to democracy and free market capitalism was introduced.

The current political structure dates from 1991, when a democratic constitution was adopted. Bulgaria is a member of the European Union, NATO, the Council of Europe, a founding state of the OSCE, and was a member of the UN Security Council three times. It is a unitary state with a high degree of political, administrative and economic centralization, and it is considered a free country.

The population of 7.36 million people is predominantly urban and mainly concentrated in the administrative centers of its 28 provinces. With 1.2 million people, the capital Sofia is the largest city and the center of most commercial and cultural activities. The strongest sectors of the economy are heavy industry, power engineering and agriculture, all relying on local natural resources. Bulgaria is home of some of the most ancient cultural artifacts in the world and a historical crossroad of various civilizations