2. Denmark and Norway (April 9, 1940): Germany launched Operation Weserübung, invading Denmark and Norway in a surprise attack. Denmark surrendered within hours, while Norway's resistance eventually forced Germany to occupy the country.
3. Belgium, the Netherlands, and Luxembourg (May 10, 1940): Germany initiated Fall Gelb (Case Yellow), attacking Belgium, the Netherlands, and Luxembourg. The Netherlands surrendered in five days, Belgium held out for 18 days, and Luxembourg was quickly taken.
4. France (May 10, 1940): As part of Fall Gelb, Germany also invaded France through Belgium and Luxembourg. French resistance collapsed after six weeks, leading to an armistice and the establishment of the collaborationist Vichy government in southern France.
5. Yugoslavia and Greece (April 6, 1941): Germany intervened in the Balkans, launching an invasion of Yugoslavia and Greece (Operation Marita). Yugoslavia surrendered in 11 days, while Greece resisted until June 1941.
6. Soviet Union (June 22, 1941): Operation Barbarossa marked Germany's largest and most ambitious invasion during World War II. Despite initial successes, Germany failed to conquer the Soviet Union, ultimately leading to the defeat of Nazi Germany.