Die Welle is The Wave
Fast paced movie about a classroom experiment in fascism, where the teacher gets it going and the kids take it from there, getting carried away as things get out of control. Loosely based on the true story of "The Third Wave" classroom experiement taught by teacher Ron Jones in Palo Alto, California at Cubberley High School in 1967. (others may remember the 1981 TV movie by Norman Lear called "The Wave", also based on the true story, and the novelization of that movie in the book "The Wave" by Todd Strassser aka Morton Rhue)
This version updates the story, taking it well beyond what originally happened, as it is set in a current-day German high school and enhanced with contemporary elements. The ending is not suited for young children. It will get you talking about fascism, extremist groups, gangs, bullying, etc.
You can learn more about the original Wave story, and variations since, at:
thewavehome.com