from Wikipedia Sofia:
Sofia listen (Bulgarian: София, IPA: [ˈsɔ.fi.ja]), is the capital and largest city of the Republic of Bulgaria, with a population of 1,346,665 in the Capital Municipality. It is located in western Bulgaria, at the foot of the mountain massif Vitosha, and is the administrative, cultural, economic, and educational centre of the country.
One of the oldest cities in Europe, the history of Serdica-Sredets-Sofia can be traced back some 7000 years ago - prehistoric settlements were excavated in the centre of the present city - near the royal palace, as well as in outer districts such as Slatina and Obelia. The well preserved town walls (especially their substructures) from antiquity date back before the 7th century BC, when Thracians established their city next to the most important and highly respected mineral spring, still functioning today. Sofia has had several names in the different periods of its existence, and remnants of the city's millenary history can still be seen today alongside modern landmarks.