Das Experiment (2001, Oliver Hirschbiegel)
Had this on my watchlist for ages.
It's very similar to Gansel's Die Welle where a social experiment goes wrong! What's great about this movie is that it's so realistic. Nothing happens that it couldn't happen on real life with real people on a situation like this one.
I love how every type of personality is transformed into a character and how can things go out of the control so fast!
The germans really know how to make great cinema!
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