The Republic of Bulgaria is located in the southeastern part of Europe, commonly known as the Balkan Peninsula or The Balkans. Thracians, Greeks and Romans occupied the territories of Bulgaria, prior to the separation from the Byzantine Empire and the establishment of the First Bulgarian Empire in 681 by Khan Asparukh. The territory of Bulgaria is about 110,000sq/km with population of 7 200 000. Sofia is the capital and largest city of Bulgaria with population of 1 200 000. Other major centers include Plovdiv, Varna, Burgas, Ruse. The southwest of the country is mountainous and home of the highest point of the Balkan Peninsula, Musala peak at 2925 meters in Rila Mountain. The Balkan Mountains laterally divide the country, with the Danube plane situated to the north. More than one-third of the country is covered by forests and the biodiversity is preserved in a number of national parks and biosphere reserves. The geographical location and landscape of Bulgaria allow for the development of both winter and summer resorts, making it a popular destination among tourists from around the world. More than 4 million people visited Bulgaria in 2011 alone.