The city is located at the foot of Vitosha Mountain in the western part of the country, within less than 50 kilometres (31 mi) drive from the Serbian border. Its location in the centre of the Balkan peninsula means that it is the midway between the Black Sea and the Adriatic Sea, whereas the Aegean Sea is the closest to it. Sofia has been an area of human habitation since at least 7000 BC. Being Bulgaria's primate city, Sofia is a hometown of many of the major local universities, cultural institutions and commercial companies. Sofia is one of the top 10 best places for start-up business in the world, especially in IT technologies. Sofia is Europe's most affordable capital to visit as of 2013.