There are numerouse moniments of culture one can visit while being in Sofia. During the conference, some of them will be freely accecible for participants & attendies with badges.

St. Alexander Nevsky CathedralUntil recent St. Alexander Nevsky Cathedral was the largest church on the Balkans. It’s magnificent interior is accessible for free. The crypt of the cathedral is converted into Museum for christian art, with a collection of precious orthodox icons from the Middle Ages and the Bulgarian National Revival periods. The entry fee for the Museum is 6 BGN and it is open Tuesday to Sunday from 10 am to 6 pm.No entry fee for the Cathedral/ Paid for the crypt
St. George Rotonda ChurchOldest church in use in Europe, dating from the 4th c. Frescoes from the 6th, 9th, 12th, 14th, 16 th c. No entry fee.No entry fee
St. Sofia Basilica and Roman Catacombs Dating from the middle of the 6th c. the current church is built on top of a Late Antiquity necropolis,  with frescoed tombs and remnants of the first two churches from the 4th and 5th centuries. The underground museum  is accessible free of charge with a meeting attendee’s badge and it’s open Monday to Sunday from 10 am to 5:30 pm. accessible with conference’ badge, otherwise entry fees may be applied
National Archaeological Institute with Museum The National Archaeological Museum is housed in a former Ottoman mosque. The artefacts in it’s collection range from Prehistoric times to Late Medieval era. A must visit. 
Working hours: Monday to Sunday.  10 am to 6pm. No entry fee with a meeting attendee’s badge.
accessible with conference’ badge, otherwise entry fees may be applied
Sofia History MuseumAs stated the Museum shows Sofia’s history from the Neolithic period to everyday lives of people during the 20th century. The museum is housed in Sofia thermal baths, built at the beginning or the twentieth century. North of the museum, across the street are the thermal springs, which Sofia was famous for since ancient times.  A must visit.
Working hours: Monday to Sunday 10 am to 6 pm. No entry fee with a meeting attendee’s badge.
accessible with conference’ badge, otherwise entry fees may be applied
Serdica Ancient cultural and communicative complexThe Largo zone is located under “Nezavisimost” square. There is an exhibition and seminar hall under the domes, as well as an information point with free access for the citizens and the guests of Sofia. In the “Archaeological remains” zone under “Maria Luisa” boulevard parts of the ancient street can be seen, as well as cult and residential buildings, water supply and sewerage systems, inner courtyards and other aspects of the Roman city of Serdica. This zone also includes the archaeological exhibition “Ancient Serdica”, where visitors may see multimedia elements, information panels and display cases with artifacts, discovered during the archaeological excavations of the site. No entrance fee with a meeting attendee’s badge. Working hours: Monday to Sunday; 10 am to 6 pm.Free
Saint Petka Samardzhiyska Medieval ChurchMedieval Church, built on top a roman crypt, with well preserved Late Medieval frescoes. Working hours 8-17. There maybe an entrance fee applied.Free
Archaeological park “Western gate of Serdica” and Catholic Cathedral St. JosefNo entry fee. The working hours of the Archeological park are 9 am to 5 pm. The Catholic Cathedral isn’t open at any given time. Free
Triangular defense tower of Serdica Excavated defense tower of Serdica, dating from the 5th c.  No entry fee. Working hours: 10 am to 6 pm. Free
Northeastern wall and tower of SerdicaExcavated ruins of the northeastern defensive fortifications of Serdica. No entry fee. Free
Prince Alexander Battenberg’s Mausoleum The Mausoleum of the First Bulgarian Ruler since the Liberation of Bulgaria from the Ottoman empire in 1878. He was exiled in a coup d’etat by Russian backed Bulgarian officers in 1886. His last wish was to be buried in Bulgaria. No entry fee. Working hours Monday to Sunday,  10 am to 5 pm. Free
National Theatre “Ivan Vasov”A majestic building,  situated in one of the central public gardens of Sofia.Free
National Military Museum The collection of the National Museum of Military History ranges from ancient bronze plates to modern tanks.  Outer yard is free of charge, visit to the inner yard and the exhibition costs 12 BGN. Working hours: Monday to Sunday, 10 am to 6 pm.Entry fee required
Kvadrat 500Kvadrat 500, the newest and largest building of the National Gallery, opened on 25 May 2015. Some 1,700 artworks from the gallery’s rich fund of over 42,000 museum pieces by Bulgarian and foreign artists are exhibited in 28 halls on four levels. The Bulgarian collection dates back to the 1890s, while the greater part of the foreign collection was formed in the 1980s.
The exposition features works tracing the path of Bulgarian art from the mid-19th century and from the 20th century, European art from the 15th–19th centuries, and art exhibits from Asia, Africa, and America.
Entry fee required
Sofia University BookstoreConference participants & attendees get  35% off the price of a book,  published by Sofia University Press with their conference’ badge.Conference badges required