All those three territories were invaded by the Axis powers prior to World War II.
-RHINELAND: On March 7, 1936, the German forces occupied the Rhineland, violating one of the points established in the Treaty of Versailles: the prohibition of Germany stationing military forces of any kind in the border region with France and Belgium, without the prior permission of such states.
-ETHIOPIA: Between October of 1935 and May of 1936 the Italian Invasion of Ethiopia occurred. This was seen as a sample of the expansionist policy that characterized the Axis Powers and the inefficiency of the League of Nations before the outbreak of World War II.
-AUSTRIA: On March 12, 1938 the merger of Austria and Nazi Germany into a single nation took place, transforming Austria into a province of the Third Reich. This situation lasted until May 5, 1945, when the Allies occupied the German province of Ostmark. The Allied military government ended in 1955, when the new State of Austria was formed.
