When a country or state is taken over by another country by military force. During the Second World War, Nazi Germany occupied many countries in Europe including Poland, Lithuania, Latvia, Denmark, Norway, the Channel Islands, Northern France, Luxembourg, Belgium, the Netherlands, Yugoslavia, Serbia, and Hungary, amongst others. Germans forces also occupied various regions of the Soviet Union and joined the Axis occupation of North Africa. German-occupied nations were confronted new Nazi hierarchies and political structures in order to keep the nation functioning, which forced many to have to collaborate or cooperate with Nazi authorities. Others protested these arrangements; the original governments of some occupied countries went into exile in other countries (ex. Belgium in London) while others formed governments-in-exile by citizens in other countries.