- Michel Goya
- Self - Former Colonel, Military Historian
- Frédéric Guelton
- Self - Colonel, Historian
- Alaric Searle
- Self - Historian, University of Salford Manchester
- Christian Hartmann
- Self - Military Historian, Munich Institute of Contemporary History
- Werner Schmachteneberg
- Self - Engineer, Fortification Specialist
- Christoph Rass
- Self - Military Historian, University of Osnabrück
- Marc Halter
- Self - President of Fort Schoenenbourg
- Christopher Mack
- Self - Narrator
- David Stanley
- English Voice
- Tercelin Kirtley
- English Voice
- Adolf Hitler
- Self - Führer of Germany
- André Maginot
- Self - Minister of War of France
- Joseph Stalin
- Self - Leader of the Soviet Union
- Fritz Todt
- Self - General Plenipotentiary for Regulation of the Construction Industry
- Hans von Seeckt
- Self - Chief of Staff of the German Army
