Sofia

Sofia is the capital of Bulgaria, in a high basin in the west of the country at the foot of Mount Vitosha. The city was renamed in the 14th century after the Church of Saint Sofia, a red-brick basilica of the 6th century that still stands near the center.

Serdica, the town of the Thracian Serdi tribe, grew into a Roman city under Trajan, and Constantine the Great is said to have called it his Rome. The Rotunda of Saint George, a brick church of the 4th century hidden in a courtyard behind the presidency, is the oldest building of the city and keeps medieval frescoes inside. Under Ottoman rule Sofia was the seat of the province of Rumelia for centuries. It was chosen as the capital of the new Bulgarian state in 1879, and its first university opened at the end of the following decade.

The Alexander Nevsky Cathedral, finished in the early 20th century, has gilded domes over a neo-Byzantine church that holds thousands of worshipers. Boyana Church, on the slopes of Vitosha in the south of the city, has frescoes from 1259 that were added to the UNESCO World Heritage List for their lifelike faces. Mineral springs rise in the center, and people fill bottles with warm water from public taps beside the old Central Mineral Baths, a 20th-century building that houses the city's history museum.

Chaos, a software company founded in Sofia, makes V-Ray, a rendering program used for film effects and architectural images. Sopharma, based in the city, makes medicines such as Tabex, a smoking cessation pill made from a plant extract. Telerik, a Sofia maker of tools for software developers, was bought by the American company Progress Software in the 2010s and keeps its offices in the city.