Belgium
Germany invaded Belgium in 1914. This was part of World War I.  The opening months of the war were very bad in Belgium.  During the war Belgium took over Ruanda-Urundi (modern-day Rwanda and Burundi).  After the War, the Prussian districts of Eupen and Malmedy were added into Belgium in 1925.  The country was again invaded by Germany in 1940 and under German control until 1944.  After World War II, the people made king Leopold III leave his throne in 1951.  This is because they thought he helped the Germans.  Belgium joined NATO as a founding member.