Sofia is the capital and largest city of Bulgaria. It is situated near the geographical centre of the Balkans region, in the Sofia Basin, a troughlike valley in the western part of the country. The city is at the foot of Vitosha mountain in the western part of the country. Being in the centre of the Balkans, it is midway between the Black Sea and the Adriatic Sea, and closest to the Aegean Sea.Sofia is the 13th largest city in the European Union. It is surrounded by mountains, such as Vitosha by the southern side, Lyulin by the western side, and the Balkan Mountains by the north, which makes it the second highest European capital after Madrid. The city is built on the Iskar river, and has many mineral springs, such as the Sofia Central Mineral Baths. It has a humid continental climate. Being Bulgaria's primate city, Sofia is home of many of the major local universities, cultural institutions and commercial companies.The city has been described as the 'triangle of religious tolerance'. This is due to the fact that three colossal temples of the three world major religions - Christianity, Islam and Judaism, reside inside the borders of the city, which are the Sveta Nedelya Church, Banya Bashi Mosque and Sofia Synagogue. Sofia has been named one of the top ten best places for start-up businesses in the world, especially in information technologies.

Sofia was Europe's most affordable capital to visit in 2013. In 1979, the Boyana Church in Sofia was included onto the World Heritage List, and it was deconstructed in the Second Bulgarian Empire, holding much patrimonial symbolism to the Bulgarian Orthodox Church. With its cultural significance in Eastern Europe, Sofia is home to the National Opera and Ballet of Bulgaria, the National Palace of Culture, the Vasil Levski National Stadium, the Ivan Vazov National Theatre, the National Archaeological Museum, and the Serdica Amphitheatre. The Museum of Socialist Art includes many sculptures and posters that educate visitors about the lifestyle in communist Bulgaria.The population of Sofia declined from 70,000 in the late 18th century, through 19,000 in 1870, to 11,649 in 1878, after which it began increasing. Sofia hosts some 1.23 million residents within a territory of 492 km2, a concentration of 17.5% of the country population within the 200th percentile of the country territory. The urban area of Sofia hosts some 1.54 million residents within 5723 km², which comprises Sofia City Province and parts of Sofia Province (Dragoman, Slivnitsa, Kostinbrod, Bozhurishte, Svoge, Elin Pelin, Gorna Malina, Ihtiman, Kostenets) and Pernik Province (Pernik, Radomir), representing 5.16% of the country territory. The metropolitan area of Sofia is based upon one hour of car travel time, stretches internationally and includes Dimitrovgrad in Serbia. Unlike most European metropolitan areas, it is not to be defined as a substantially functional metropolitan area, but is of the type with "limited variety of functions". The metropolitan region of Sofia is inhabited by a population of 1.68 million and is made up of the whole provinces Sofia City, Sofia and Pernik, comprising more than 10,000 km².

• Bulgaria is the oldest country in Europe, established in 681 AD. It is also the only European country that hasn’t changed its name after the establishment
• The first subway station took 30 years to build from 1960 to 1990. Every meter they dug, they found more and more archaeological sites ranging from the era of Thracians to the Romans. They even found thermal water
• The oldest gold treasure in the world has been found on the territory of Bulgaria, at a burial site to the west of Varna city, close to the Black sea shore. During the digging were found more than 3000 golden artifacts being more than 6000 years old
• Sofia Valley boasts more than 30 mineral springs, most hotter than 33°C (91.4°F) and low in mineralization, making the water perfect for consumption (after proper cooling at least)
• At 550 m above sea level, Sofia is one of the highest capitals in Europe - after Andorra la Vella (1,023 m), San Marino (749 m), Madrid (667 m), and Pristina (652 m) - sitting at the base of Vitosha Mountain
   

Sofia Municipality is identical to Sofia City Province, which is distinct from Sofia Province, which surrounds but does not include the capital itself. Besides the city proper, the 24 districts of Sofia Municipality encompass three other towns and 34 villages. Districts and settlements have their own governor who is elected in a popular election. The assembly members are chosen every four years. The common head of Sofia Municipality and all the 38 settlements is the mayor of Sofia. The current mayor Yordanka Fandakova is serving a third consecutive term, having won the 2015 election at first round with 238,500 votes, or 60.2% of the vote, when Reformist Bloc opponent Vili Lilkov was second with 9.6%; the turnout was 41.25%. A precedent happened, due to the suspicion, as a preventative action between 300 and 5000 people and counters had been locked inside Arena Armeets against their will for two days, following which the director of the Electoral Commission of Sofia resigned at the request of Prime Minister Boyko Borisov.

Sofia is the seat of the executive , legislative and judiciary bodies of Bulgaria, as well as all government agencies, ministries, the National Bank, and the delegation of the European Commission. The President, along with the Council of Ministers, is located on Independence Square, also known as The Largo or The Triangle of Power. One of the three buildings in the architectural ensemble, the former Bulgarian Communist Party headquarters, is due to become the seat of the Parliament. A refurbishment project is due to be completed in mid-2019, while the old National Assembly building will become a museum or will only host ceremonial political events.Under Bulgaria's centralised political system, Sofia concentrates much of the political and financial resources of the country. Nevertheless, in the 21st century, crimes, including Bulgarian mafia killings, caused problems in the city, where authorities had difficulties convicting the actors, which had caused the European Commission to warn the Bulgarian government that the country would not be able to join the EU unless it curbed crime . Many of the most severe crimes are contract killings connected to organised crime, but these had dropped in recent years after several arrests of gang members. Corruption in Bulgaria also affects Sofia's authorities. According to the director of Sofia District Police Directorate, the largest share of the crimes are thefts, making up 62.4% of all crimes in the capital city. Increasing are frauds, drug-related crimes, petty theft and vandalism. According to a survey, almost a third of Sofia's residents say that they never feel safe in the Bulgarian capital, while 20% always feel safe. As of 2015, the consumer-reported perceived crime risk on the Numbeo database was “high” for theft and vandalism and “low” for violent crimes; safety while walking during daylight was rated «very high», and “moderate” during the night.
 

Sofia is the economic hub of Bulgaria and home to most major Bulgarian and international companies operating in the country, the National Bank and the Bulgarian Stock Exchange. The city's GDP (PPS) per capita stood at €29,600 ($33,760) in 2015, one of the lowest for a capital region in the EU, but well above other cities in the country. Nominal GDP in 2014 was 32.8 billion leva ($19.1 billion) The average per capita annual income was 6,890 leva ($4,019) in 2014, and average monthly wages in June 2018 were $880, the highest nationally. Services dominate the economy, accounting for 85.9% of gross value added. In 2015, Forbes listed Sofia as one of the top 10 places in the world to launch a startup business, because of the low corporate tax (10%), the fast internet connection speeds available – one of the fastest in the world, and the presence of several investment funds, including Eleven Startup Accelerator, LAUNCHub and Neveq.

Historically, after World War II and the era of industrialisation under socialism, the city and its surrounding areas expanded rapidly and became the most heavily industrialised region of the country. The influx of workers from other parts of the country became so intense that a restriction policy was imposed, and residing in the capital was only possible after obtaining Sofianite citizenship. However, after the political changes in 1989, this kind of citizenship was removed. In 2015, Globalization and World Cities Research Institute ranked Sofia as Beta- world city. As of 12 September 2018, Sofia is ranked among the 100 financial top centres worldwide. Up until 2007, Sofia experienced rapid economic growth. In 2008, apartment prices increased dramatically, with a growth rate of 30%. In 2009, prices fell by 26%. In January 2015, Sofia was ranked 30th out of 300 global cities in terms of combined growth in employment and real gross domestic product (GDP) per capita in 2013–2014. This was the highest rank amongst cities in Southeast Europe. The real GDP (PPP) per capita growth was 2.5% to $33,105 (28,456 euro) and the employment went up by 3.4% to 962,400 in 2013–2014.

With its developing infrastructure and strategic location, Sofia is a major hub for international railway and automobile transport. Three of the ten Pan-European Transport Corridors cross the city: IV, VIII and X. All major types of transport are represented in the city. The Central Railway Station is the primary hub for domestic and international rail transport, carried out by Bulgarian State Railways , the national rail company headquartered in the city. It is one of the main stations along BDZ Line 1, and a hub of Lines 2, 5 and 13. Line 1 provides a connection to Plovdiv, the second-largest city in Bulgaria, while Line 2 is the longest national railway and connects Sofia and Varna, the largest coastal city. Lines 5 and 13 are shorter and provide connections to Kulata and Bankya, respectively. Overall, Sofia has 186 km of railway lines.Sofia Airport handled 6,962,040 passengers in 2018.Public transport is well-developed with bus 2,380 km , tram 308 km and trolleybus 193 km lines running in all areas of the city. In 2015 new 7 stations were opened and the underground extends to Sofia Airport on its Northern branch and to Business Park Sofia on its Southern branch. In July 2016 the Vitosha Metro Station was opened on the M2 main line. A third line is currently under construction and is expected to be finished in the second half of 2019. This line will complete the proposed underground system of three lines with about 65 km of lines. The master plan for the Sofia Metro includes three lines with a total of 63 stations. Marshrutkas provide an efficient and popular means of transport by being faster than public transport, but cheaper than taxis. There are around 13,000 taxi cabs operating in the city. Additionally, all-electric vehicles are available through carsharing company Spark, which is set to increase its fleet to 300 cars by mid-2019.

The municipality was known for minor and cosmetic repairs and many streets are in a poor condition. This is noticeably changing in the past years. There are different boulevards and streets in the city with a higher amount of traffic than others. These include Tsarigradsko shose, Cherni Vrah, Bulgaria, Slivnitsa and Todor Aleksandrov boulevards, as well as the city's ring road, where long chains of cars are formed at peak hours and traffic jams occur regularly. Consequently, traffic and air pollution problems have become more severe and receive regular criticism in local media. The extension of the underground system is hoped to alleviate the city's immense traffic problems. Sofia has an extensive district heating system based around four combined heat and power plants and boiler stations.