What is factors contribute to the outbreak of world war 2 in Europe?

Several factors contributed to the outbreak of World War II in Europe, including the harsh conditions of the Treaty of Versailles, which left Germany economically weakened and politically unstable. The rise of totalitarian regimes, particularly Adolf Hitler's Nazi Germany, fueled aggressive expansionism and militarism. Additionally, the failure of the League of Nations to maintain peace and the policy of appeasement adopted by Western powers allowed these aggressions to go unchecked, ultimately leading to the invasion of Poland in 1939 and the start of the war.