1. Treaty of Versailles—harsh terms, German resentment, political instability 2. League of Nations—ineffectiveness, lack of enforcement, US absence, key failures 3. Appeasement—Chamberlain′s policy, Munich Agreement, delayed response to aggression 4. Cold War tensions—iron curtain, superpower rivalry, ideological divide 5. Berlin crises—Blockade, Airlift, Wall construction, symbolic and strategic implications 6. Soviet suppression—Hungary 1956, Prague Spring 1968, Brezhnev Doctrine enforcement