Vasil Levski (Bulgarian: , spelled in old Bulgarian orthography as , pronounced [vsi lfski]), born Vasil Ivanov Kunchev ( ; 18 July 1837 18 February 1873), was a Bulgarian revolutionary who is, today, a national hero of Bulgaria. Dubbed the Apostle of Freedom, Levski ideologised and strategised a revolutionary movement to liberate Bulgaria from Ottoman rule. Levski founded the Internal Revolutionary Organisation, and sought to foment a nationwide uprising through a network of secret regional committees.

Born in the Sub-Balkan town of Karlovo to middle-class parents, Levski became an Orthodox monk before emigrating to join the two Bulgarian Legions in Serbia and other Bulgarian revolutionary groups. Abroad, he acquired the nickname Levski ("Lionlike"). After working as a teacher in Bulgarian lands, he propagated his views and developed the concept of his Bulgaria-based revolutionary organisation, an innovative idea that superseded the foreign-based detachment strategy of the past. In Romania, Levski helped institute the Bulgarian Revolutionary Central Committee, composed of Bulgarian expatriates. During his tours of Bulgaria, Levski established a wide network of insurrectionary committees. Ottoman authorities, however, captured him at an inn near Lovech and executed him by hanging in Sofia.

Levski looked beyond the act of liberation and envisioned a Bulgarian republic of ethnic and religious equality, largely reflecting the liberal ideas of the French Revolution and contemporary Western society. He said, "We will be free in complete liberty where the Bulgarian lives: in Bulgaria, Thrace, Macedonia; people of whatever ethnicity live in this heaven of ours, they will be equal in rights to the Bulgarian in everything." Levski held that all religious and ethnic groups live in a free Bulgaria enjoy equal rights. He is commemorated with monuments in Bulgaria and Serbia, and numerous national institutions bear his name. In 2007, he topped a nationwide television poll as the all-time greatest Bulgarian.

Bulgaria ( (listen); Bulgarian: България, romanized: Bǎlgariya), officially the Republic of Bulgaria, is a country in Southeast Europe. It occupies the whole 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 a territory of 110,994 square kilometres (42,855 sq mi), and is the sixteenth-largest country in Europe. Sofia is the country's capital and largest city; other major cities are Plovdiv, Varna and Burgas.

One of the earliest societies in the lands of modern-day Bulgaria was the Neolithic Karanovo culture, which dates back to 6,500 BC. In the 6th to 3rd century BC the region was a battleground for ancient Thracians, Persians, Celts and Macedonians; stability came when the Roman Empire conquered the region in AD 45. After the Roman state splintered, tribal invasions in the region resumed. Around the 6th century, these territories were settled by the early Slavs. The Bulgars led by Asparuh of Bulgaria attacked from the lands of (Old Great) Bulgaria and permanently invaded the Balkans in the late 7th century. They established (Danubian) Bulgaria, victoriously recognised by treaty in AD 681 by the Eastern Roman Empire. It dominated most of the Balkans and significantly influenced Slavic cultures by developing the Cyrillic script. The First Bulgarian Empire lasted until the early 11th century, when Byzantine emperor Basil II conquered and dismantled it. A successful Bulgarian revolt in 1185 established a Second Bulgarian Empire, which reached its apex under Ivan Asen II (1218–1241). After numerous exhausting wars and feudal strife, the empire disintegrated in 1396 and fell under Ottoman rule for nearly five centuries.

The Russo-Turkish War of 1877–78 resulted in the formation of the third and current Bulgarian state. Many ethnic Bulgarians were left outside the new nation's borders, which stoked irredentist sentiments that led to several conflicts with its neighbours and alliances with Germany in both world wars. In 1946, Bulgaria came under the Soviet-led Eastern Bloc and became a socialist state. The ruling Communist Party gave up its monopoly on power after the revolutions of 1989 and allowed multiparty elections. Bulgaria then transitioned into a democracy and a market-based economy. Since adopting a democratic constitution in 1991, Bulgaria has been a unitary parliamentary republic composed of 28 provinces, with a high degree of political, administrative, and economic centralisation.

Bulgaria is a developing country, with an upper-middle-income economy, ranking 56th in the Human Development Index. Its market economy is part of the European Single Market and is largely based on services, followed by industry—especially machine building and mining—and agriculture. Widespread corruption is a major socioeconomic issue; Bulgaria ranked as the most corrupt country in the European Union in 2018. The country also faces a demographic crisis, with its population shrinking annually since around 1990; it currently numbers roughly seven million, down from a peak of nearly nine million in 1988. Bulgaria is a member of the European Union, NATO, and the Council of Europe; it is also a founding member of the OSCE, and has taken a seat on the United Nations Security Council three times.