How and why did World War 2 start?

Answer 1

WW2 started because Japan, Italy and Germany wanted land and territory and they regarded the rest of the world as being too weak and soft to fight back. The League of Nations failed to respond to aggression as did many of the world's leaders, such as British Prime Minister Neville Chamberlain. Another reason was the Great Depression. Many countries were poor and needed money and resources to restore their economies and help their peoples.
Germany sought to regain the lands lost as a result of WWI and so it invaded Poland. Hitler's aggressive acquisition of territory began in 1936 when he ordered his army to reoccupy the Rhineland district of Germany. Bordering France, the Rhineland had been designated as a demilitarized zone by the Versailles Treaty ending World War I. It was a high-risk endeavor for Hitler. The German troops were unprepared, poorly equipped and had orders to retreat if the French offered any resistance. In the end, the maneuver went smoothly without any hindrance. Encouraged by this result, Hitler went on to absorb Austria and the German dominated Sudetenland area of Czechoslovakia into the German Third Reich in 1938. In March of the next year he occupied the remainder of Czechoslovakia

Answer 2

World War 2 started in 1939 when Nazi Germany invaded Poland. The invasion was a violation of the Treaty of Versailles and triggered a series of alliances and declarations of war. The war escalated due to a combination of factors, including territorial ambitions of Germany, the aggressive expansion of Japan, economic tensions, and unresolved issues from World War 1.