Leningrad: The Russian Museum
This very nice Soviet postcard of the Russian Museum in Leningrad was printed in the USSR in 1976. I could tell you where I got it, but then I’d have to kill you.
From the arrangement of the printing on the back (and the lack of a stamp box), it’s not clear that this is actually intended to be a postcard — though it is of the proper size and card stock. Perhaps, if you were mailing it from the USSR, the printing on the left is intended to discourage you from writing a personal message — which would probably have been censored anyway.