Berlin wall, for one. Yeah, it was done by the German Democratic Republic, not the USSR, but DDR was a puppet of the USSR, so the USSR is culpable here, just as the USA today is culpable for what Israel is doing.

Supposedly build to keep fascists out, but if that were true, they’d have build it the other way around. If you shoot at a fascist before they attack the rampart, you start an offensive war with West Germany, which you don’t want. Meaning, a theoretical attacker on the West German side of the wall could roll up with heavy construction equipment and just knock the strongest part of the defense down, before shooting back is allowed. In fact, since the wall is opaque, the guards wouldn’t even know what is happening until the wall is breached. Which is probably why the West Germans got to decorate their side of the wall. Of course, no West German would have a reason to breach the wall, because they were just allowed to cross over at the official check points.