The atmosphere in Sofia is not that of a large European capital : you feel more like being in some provincial town. The suburbs mostly consist of gray decaying soviet style apartment blocks. The center however, with its paved streets and large squares, is nice and quiet.
Sofia was settled by the Serdi some 3000 years ago, then named Serdica by the Romans. It reached a peak under Constantine, but was sacked by the Huns in the 5th century. It was then one of the main Byzantine cities in the Balkans. From the 7th century onwards, Slavs migrated to the area, and Khan Krum took the city in 809. It was then named Sredets and changed again to Triaditsa. It's only in the 14th century that it acquired its present name. The Ottomans captured Sofia in 1382. It was reduced to a minor provincial town in 1878, at the time of the Liberation. Yet it was chosen as capital for its location and possibility of growth. After World War II, Stalinist monumentalism invaded the city, changing many of its previous features. The party house (built in 1950) is probably the best example of this period.
Though the city has no real stunning sight, there are a few nice churches, especially the Alexandâr Nevski memorial church, which was built to honor the 2000000 Russian casualties of the War of Liberation. Sveta Nedelya was rebuilt many times, and changed names very often. It's the place where a failed bomb attack on Tsar Boris killed 123 people in 1923. A little jewel of a church, the Rotunda of Sveti Georgi (of which I unfortunately have no pictures), sits in a weird location: little a courtyard surrounded by high buildings. It is Sofia's oldest church (built in the 4th century) and has very nice frescoes, most of which are from the 14th century.