When Hitler invaded Poland, Britian finially came to action. They told Hitler he needed to leave Poland or else, Hitler ignored this threat and soon Britain and France declrared war.
The Treaty Of Versailes powered the anger and resentment behind Germany. Hitler and the Nazi Party relied on this for support through propoganda.
The Leage of Nations along with Britain and France followed a policy of appeasement to Hitler. Not wanting a second war made The League of Nations ineffective.
World War 1 left Germany poor and in debt so The Great Depression hit hard.
The Depression brings a stop to international trade, making the economic situation worse in Germany and Europe. This leaves the countrys at a vaulunable spot and Hitler rises to power with the promise of fixing it.