
Operation Achse, originally called Operation Alaric, was the codename for the German operation supported by Italian fascists to forcibly disarm the Italian armed forces after Italy's armistice with the Allies on 3 September 1943. The Germans disarmed over a million Italian troops within a matter of days, annihilating the Italian military and state.

The Invasion of Åland was a 1918 military campaign of World War I in the Åland Islands, Finland. The islands, still hosting Soviet Russian troops, were first invaded by Kingdom of Sweden in late February and then by the German Empire in early March. The conflict was also related to the Finnish Civil War including minor fighting between the Finnish Whites and the Finnish Reds.

The Anschluss, also known as the Anschluss Österreichs, refers to the annexation of Austria into Nazi Germany on 12 March 1938.

The Battle of Belgium or Belgian Campaign, often referred to within Belgium as the 18 Days' Campaign, formed part of the greater Battle of France, an offensive campaign by Germany during the Second World War. It took place over 18 days in May 1940 and ended with the German occupation of Belgium following the surrender of the Belgian Army.

The German invasion of Belgium was a military campaign which began on 4 August 1914. Earlier, on 24 July, the Belgian government had announced that if war came it would uphold its historic neutrality. The Belgian government mobilised its armed forces on 31 July and a state of heightened alert was proclaimed in Germany. On 2 August, the German government sent an ultimatum to Belgium, demanding passage through the country, and German forces invaded Luxembourg. Two days later, the Belgian government refused the demands and the British government guaranteed military support to Belgium. The German government declared war on Belgium on 4 August, troops crossed the border and began the Battle of Liège.

The Battle of Crete was fought during the Second World War on the Greek island of Crete. It began on the morning of 20 May 1941, when Nazi Germany began an airborne invasion of Crete. Greek and other Allied forces, along with Cretan civilians, defended the island. After one day of fighting, the Germans had suffered heavy casualties and the Allied troops were confident that they would defeat the invasion. The next day, through communication failures, Allied tactical hesitation and German offensive operations, Maleme Airfield in western Crete fell, enabling the Germans to land reinforcements and overwhelm the defensive positions on the north of the island. Allied forces withdrew to the south coast. More than half were evacuated by the British Royal Navy and the remainder surrendered or joined the Cretan resistance. The defence of Crete evolved into a costly naval engagement; by the end of the campaign the Royal Navy's eastern Mediterranean strength had been reduced to only two battleships and three cruisers.
The German invasion of Denmark was the German attack on Denmark on 9 April 1940, during the Second World War. The attack was a prelude to the main attack against Norway.

The Battle of France, also known as the Fall of France, was the German invasion of France and the Low Countries during the Second World War. On 3 September 1939 France had declared war on Germany, following the German invasion of Poland. In early September 1939, France began the limited Saar Offensive. By mid-October, the French had withdrawn to their start lines. In six weeks from 10 May 1940, German forces defeated Allied forces by mobile operations, conquering France, Belgium, Luxembourg and the Netherlands, ending land operations on the Western Front until the Normandy landings on 6 June 1944. Italy entered the war on 10 June 1940.

The Battle of Greece is the common name for the invasion of Allied Greece by Fascist Italy and Nazi Germany in April 1941 during World War II. The Italian invasion in October 1940, which is usually known as the Greco-Italian War, was followed by the German invasion in April 1941. German landings on the island of Crete came after Allied forces had been defeated in mainland Greece. These battles were part of the greater Balkan Campaign of Germany.

The Historiography of the Battle of France describes how the German victory over French and British forces in the Battle of France had been explained by historians and others. Many people in 1940 found the fall of France unexpected and earth shaking. Alexander notes that Belgium and the Netherlands fell to the German army in a matter of days and the British were soon driven back to the British Isles,But it was France's downfall that stunned the watching world. The shock was all the greater because the trauma was not limited to a catastrophic and deeply embarrassing defeat of her military forces – it also involved the unleashing of a conservative political revolution that, on 10 July 1940, interred the Third Republic and replaced it with the authoritarian, collaborationist Etat Français of Vichy. All this was so deeply disorienting because France had been regarded as a great power....The collapse of France, however, was a different case.

The German invasion of Luxembourg was part of Case Yellow, the German invasion of the Low Countries—Belgium, Luxembourg and the Netherlands—and France during World War II. The battle began on 10 May 1940 and lasted just one day. Facing only light resistance, German troops quickly occupied Luxembourg. The Luxembourgish government, and Grand Duchess Charlotte, managed to escape the country and a government-in-exile was created in London.

The Battle of the Netherlands was a military campaign part of Case Yellow, the German invasion of the Low Countries and France during World War II. The battle lasted from 10 May 1940 until the surrender of the main Dutch forces on 14 May. Dutch troops in the province of Zealand continued to resist the Wehrmacht until 17 May when Germany completed its occupation of the whole country.

Operation Sea Lion, also written as Operation Sealion, was Nazi Germany's code name for the plan for an invasion of the United Kingdom during the Battle of Britain in the Second World War. Following the Fall of France, Adolf Hitler, the German Führer and Supreme Commander of the Armed Forces, hoped the British government would accept his offer to end the war, and he reluctantly considered invasion only as a last resort if all other options failed.

Operation Weserübung was the code name for Germany's assault on Denmark and Norway during the Second World War and the opening operation of the Norwegian Campaign.

The Invasion of Yugoslavia, also known as the April War or Operation 25, was a German-led attack on the Kingdom of Yugoslavia by the Axis powers which began on 6 April 1941 during World War II. The order for the invasion was put forward in "Führer Directive No. 25", which Adolf Hitler issued on 27 March 1941, following the Yugoslav coup d'état.