ADOLF HITLER

Adolf Hitler became president, or as he used to call himself "führer" after President Hindenburg's dead in 1934. He started his totalitarian dictatorship by making The Army swore full loyalty to him. Before he became Führer, he was the Chancellor of Germany, because after losing presidential elections against Hindenburg, he talked to the Nazi Party (the political party that he belonged to) and they talked to the President, so Hindenburg made him Chancellor.

After Hitler reaching full power, he started to spread around Germany his ideology,the NAZI ideology. This ideology consisted on the thought that the Aryan Race , the only pure race around the world and the only one that should exist. Another idea was that Jews, Gypsies and homosexuals were not called humans at all, they considered that their life was unworthy and that they deserve to die.

Also, Adolf Hitler implements Nazi redevelopment, reindustrialization, and rearmament of Germany. Some of the military actions that Hitler took just before the war were that the Nazis eliminated the people that are against them through a process known as Gleichschaltung.
Hitler publicly announced that the German army would be expanded to 600,000 men (six times the number stipulated in the Treaty of Versailles), and the introduction of an Air Force (Luftwaffe) and increasing the size of the Navy (Kriegsmarine).

Just After the World War II started, secret political groups were made.

The Gestapo: Was the official secret police of Nazi Germany and German-occupied Europe.
The Schutzstaffel: Was a major paramilitary organization under Adolf Hitler and the Nazi Party (NSDAP).

One of Hitler's unlikeable characteristics was that he made very convincing and great speeches, so he got the Germans to be fully loyal to him.

http://remember.org/guide/Facts.root.hitler.html