What are the commemorative coins of the Soviet Union (USSR)?
Excuse me, I'm curious about the commemorative coins issued by the Soviet Union, or the USSR as it was commonly known. Could you possibly explain what these coins were? Were they produced to commemorate significant events or historical figures? Did they feature any specific designs or symbols? Also, how were these coins used within the Soviet Union and how do they hold value today for collectors? I'm quite fascinated by the history and culture of the Soviet era, and these coins seem like a fascinating piece of that puzzle.