Bulgaria is a country in Southeast Europe. It is situated in the eastern part of the Balkans and is bordered by Romania to the north, Serbia and North Macedonia to the west, Greece and Turkey to the south, and the Black Sea to the east. Bulgaria covers an area of 110,994 square kilometers and is the sixteenth-largest country in Europe. Its capital and largest city is Sofia. Bulgaria is a developing country with an upper-middle-income economy, ranking 68th in the Human Development Index. Its market economy is part of the European Single Market and is largely based on services, followed by industry and agriculture. Bulgaria is a member of the European Union, NATO, and the Council of Europe.