The National Palace of Culture is another landmark of the city of Sofia. This is used as a concert hall and congress center and, as you can easily see, was built during the communist era of Bulgaria for the 1300th birthday of the Bulgarian nation in 1981. Even before the 1980s, the Communist Unity Party of Bulgaria expressed the desire for a cultural center in the capital. This was realized in the 80s of the twentieth century.
Detailed information is available in English: ndk.bg