After the end of World War I, defeated Germany was not satisfied with the results of peace treaties and they considered to be drastically impaired. Discontent began to increase when Adolf Hitler became a leader. He accelerated the armament and, with the people who shared his beliefs, was devising a plan on how to upgrade strategic and geopolitical power of Germany. Great Britain was marked as the main enemy, and the main principle of parrying them, and later defeating them, was to build a strong navy. When the war with Great Britain arose, the German navy had the mission to establish control over the Atlantic, which was the vital centre for trades and transport of ores. In the begging of World War II, the navy, whose leader was Raeder, had a lot of success and, when they conquered Norway and France, they obtained good strategic centres for the attack on Great Britain. However, the course of war started to change with the formation of more battlefields where Germany had to participate, as well as US’ entry to the war. Hitler began to lose control of all territories, including the Atlantic, where the Allies secured the control on and below the sea surface.