The Slovak Radio Building
alluringworld.com
alluringworld.com
Hold on... the existence of a concert hall for the performance of classical music equipped with a fairly serious looking organ does not strike me as being especially Soviet. For example, my home venue...
https://en.wikipedia.org/wiki/Symphony_Hall,_Birmingham
The building described in the OA looks wonderful! They should capitalise on it!
I took the "still looks like a socialist museum" to be referring to the second part of the sentence: "the whole interior has been left as it was 30 years ago".
After Stalinism subsided, the USSR spent a small fortune promoting Russian culture, esp. classical music, at home and abroad.
E.g. Warsaw in Poland was "gifted" a huge Palace of Culture and Science, which included a concert hall which was used for classical and pop concerts.
Czechoslovakia was not part of the Soviet Union.