It's not clear how successful the USSR really was in getting people not to believe in God.

[EDITED to add:] Actually, I don't know whether it's clear how successful the USSR was in getting people not to believe in God. What I know is that (1) I don't know and (2) I have a hazy recollection of having heard things that suggest it wasn't terribly successful (a big increase in overt religiousness after the fall of the USSR, stories of somewhat-underground Christianity while it was still in place, that sort of thing). So let me instead make it a question: How successful, actually, was the USSR in getting people not to believe in God?