I checked out two from the library that were very good. One was "Katyn," a Polish movie about the murders of the Polish officer corps by the Russians in 1940 in Katyn forest. Addressed issues I hadn't even considered, like them trying to convince the Poles that the Germans had done it when they invaded in 1941, and the aftereffects of it while living under the Russian regime for 40-something years afterward.
Also "Die Welle," or "The Wave," a German film about teaching a group of students about authoritarianism, and the project going out of control during one week.
I recommend both. Unless you can't handle subtitles.