Day 1 — Alexander Nevsky, Serdica & the City Centre
Start at Alexander Nevsky Cathedral, the neo-Byzantine landmark that dominates every photograph of Sofia. Built in 1912 and seating 5,000, it's decorated with gold leaf, onyx, and Italian marble. The crypt houses one of the world's best collections of Bulgarian icons. Behind it sits St Sofia Church — smaller, older, and the origin of the city's name — and around it a small flea market of Soviet memorabilia and antiques runs most days.
From there, walk into the centre and down into Sofia's deepest layer: Serdica, the Roman city that once stood here. Serdika metro station has ruins visible directly beneath the platforms; a short walk away, the open-air archaeological complex beside the Sheraton Sofia hotel exposes a 4th-century Roman forum, complete with the Rotunda of St George, a red-brick church that has survived as a Roman temple, an Ottoman mosque, and now a working Orthodox church across nearly 1,700 years.
Lunch near Vitosha Boulevard, then spend the afternoon walking the boulevard itself down to NDK (the National Palace of Culture), Sofia's largest cultural venue and a good marker of where the pedestrian centre ends. Dinner at a mehana for kavarma and rakiya, then an evening drink on Vitosha Boulevard.
Day 2 — Boyana Church, the Largo & Communist Sofia
Morning: head south to Boyana Church, a UNESCO World Heritage Site in the foothills of Vitosha Mountain. Its 13th-century frescoes are remarkable for their naturalism — faces with individual character decades before anything comparable appeared in Italian painting. Entry is timed and limited to small groups; book ahead.
Back in the centre by early afternoon, walk the Largo — the monumental block of Stalinist architecture comprising the former Communist Party headquarters, the Council of Ministers, and the Presidency, arranged around Sofia's ancient Roman ruins in a striking, deliberate layering of eras. Watch the changing of the guard outside the Presidency on the hour.
The Museum of Socialist Art, a short taxi ride from the centre, is a park of relocated communist statues — a giant red star that once topped the Party House, a Lenin statue, and dozens of others — an unusually candid way a former Eastern Bloc capital deals with its recent past.
Evening: dinner in the centre and, if timing allows, a stroll through the National Garden next to the Ivan Vazov National Theatre, one of Sofia's most photogenic buildings after dark.
Day 3 — Vitosha Mountain
Sofia is one of the only European capitals with a mountain inside its city limits. Vitosha rises to 2,290m immediately south of the centre and is reachable by bus or gondola in under 40 minutes.
In warmer months, ride the gondola from Simeonovo up to Aleko, then walk out to the Golden Bridges (Zlatni Mostove) — a river of giant granite boulders running down the mountainside, a strange and popular natural landmark. Trails from Aleko are well marked and range from easy walks to a proper hike up Cherni Vrah, Vitosha's highest peak, with views stretching to the Rila and Pirin ranges on a clear day.
In winter, Vitosha becomes a functioning ski area — modest by Alpine standards but startlingly close to a capital city and cheap by European standards.
Come back down by late afternoon for a final Sofia dinner. Try a restaurant serving proper Bulgarian mountain cooking — grilled meats, banitsa, and Bulgarian wine, which is underrated and inexpensive even at the better addresses in the centre.