Sofia is the capital and largest city of the Republic of Bulgaria, with 1.4 million people living in the Capital Municipality 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. Sofia's development as a significant settlement owes much to its central position in the Balkans. A number of low rivers cross the city, including the Vladaiska and the Perlovska. The Iskar River in its upper course flows near eastern Sofia. The city is known for its numerous mineral and thermal springs. Artificial and dam lakes were built in the last century.

Sofia has a humid continental climate with high temperature amplitudes. The hottest month is August while January is the coldest. The temperatures in Sofia generally remain cooler than other parts of Bulgaria in summer, due to the high altitude of the valley in which it is situated. However temperatures can still reach up to 40 °C on occasions.