Mediterranean and Middle East theatre of World War II in the context of "Theater (warfare)"

World War II or the Second World War (1 September 1939 – 2 September 1945) was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were put on trial for war crimes.

The causes of World War II included unresolved tensions in the aftermath of World War I, the rise of fascism in Europe and militarism in Japan. Key events preceding the war included Japan's invasion of Manchuria in 1931, the Spanish Civil War, the outbreak of the Second Sino-Japanese War in 1937, and Germany's annexations of Austria and the Sudetenland. World War II is generally considered to have begun on 1 September 1939, when Nazi Germany, under Adolf Hitler, invaded Poland, after which the United Kingdom and France declared war on Germany. Poland was divided between Germany and the Soviet Union under the Molotov–Ribbentrop Pact. In 1940, the Soviet Union annexed the Baltic states and parts of Finland and Romania. After the fall of France in June 1940, the war continued mainly between Germany, now assisted by Fascist Italy, and the British Empire, with fighting in the Balkans, Mediterranean, and Middle East, the aerial Battle of Britain and the Blitz, and the naval Battle of the Atlantic. Through campaigns and treaties, Germany gained control of much of continental Europe and formed the Axis alliance with Italy, Japan, and other countries. In June 1941, Germany invaded the Soviet Union, opening the Eastern Front and initially making large territorial gains.

The military history of the United Kingdom in World War II covers the Second World War against the Axis powers, starting on 3 September 1939 with the declaration of war by the United Kingdom and France, followed by the UK's Dominions, Crown colonies and protectorates on Nazi Germany in response to the invasion of Poland by Germany. There was little, however, the Anglo-French alliance could do or did do to help Poland. The Phoney War culminated in April 1940 with the German invasion of Denmark and Norway. Winston Churchill became prime minister and head of a coalition government in May 1940. The defeat of other European countries followed – Belgium, the Netherlands, Luxembourg and France – alongside the British Expeditionary Force which led to the Dunkirk evacuation in June 1940.

Britain and its Empire continued the war against Germany. Churchill engaged industry, scientists and engineers to advise and support the government and the military in the prosecution of the war effort. Germany's planned invasion of the UK was averted by the Royal Air Force denying the Luftwaffe air superiority in the Battle of Britain, and by its marked inferiority in naval power. Subsequently, urban areas in Britain suffered heavy bombing during the Blitz in late 1940 and early 1941. The Royal Navy sought to blockade Germany and protect merchant ships in the Battle of the Atlantic. The Army counter-attacked in the Mediterranean and Middle East, including the North-African and East-African campaigns, and in the Balkans.

Operation Torch (8–16 November 1942) was an Allied invasion of French North Africa during World War II. Torch was a compromise operation that met the British objective of securing victory in North Africa while allowing American armed forces the opportunity to begin their fight against Nazi Germany and Fascist Italy on a limited scale.

The French colonies were aligned with Germany via Vichy France but the loyalties of the population were mixed. Reports indicated that they might support the Allies. The American General Dwight D. Eisenhower, supreme commander of the Allied forces in Mediterranean theater of the war, approved plans for a three-pronged attack on Casablanca (Western), Oran (Centre) and Algiers (Eastern), then a rapid move on Tunis to catch Axis forces in North Africa from the west in conjunction with the British advance from Egypt.

The Italian campaign of World War II, also called the Liberation of Italy following the German occupation in September 1943, consisted of Allied and Axis operations in and around Italy, from 1943 to 1945. The joint Allied Forces Headquarters (AFHQ) was operationally responsible for all Allied land forces in the Mediterranean theatre and it planned and led the invasion of Sicily in July 1943, followed in September by the invasion of the Italian mainland and the campaign in Italy until the surrender of the Axis forces in Italy in May 1945.

The invasion of Sicily in July 1943 led to the collapse of the Fascist Italian regime and the fall of Mussolini, who was deposed and arrested by order of King Victor Emmanuel III on 25 July. The new government signed an armistice with the Allies on 8 September 1943. However, German forces soon invaded northern and central Italy, committing several atrocities against Italian civilians and army units who opposed the German occupation and started the Italian resistance movement. Mussolini, who was rescued by German paratroopers, established a collaborationist puppet state, the Italian Social Republic (RSI), to administer the German-occupied territory. On 13 October 1943, the Allies recognized Italy as a co-belligerent in the war against Germany. Thereafter, the Italian Co-Belligerent Army and the Italian partisans fought alongside the Allies against German troops and the collaborationist National Republican Army; an aspect of this period is the Italian civil war. In the summer of 1944, after the Axis defeats at Cassino and Anzio, central Italy, including Rome, was liberated. Northern Italy was liberated following the final spring offensive and the general insurrection of Italian partisans on 25 April 1945. Mussolini was captured by the Italian resistance and summarily executed by firing squad. The campaign ended when Army Group C surrendered unconditionally to the Allies on 2 May 1945, one week before the formal German Instrument of Surrender. Both sides committed war crimes during the conflict, and the independent states of San Marino and Vatican City surrounded by Italian territory also suffered damage.

World War II or the Second World War (1 September 1939 – 2 September 1945) was a global conflict between the Allied powers and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were put on trial for war crimes.

The causes of World War II included unresolved tensions in the aftermath of World War I, the rise of fascism in Europe and militarism in Japan. Key events preceding the war included Japan's invasion of Manchuria in 1931, the Spanish Civil War, the outbreak of the Second Sino-Japanese War in 1937, and Germany's annexations of Austria and the Sudetenland. World War II is generally considered to have begun on 1 September 1939, when Nazi Germany, under Adolf Hitler, invaded Poland, after which the United Kingdom and France declared war on Germany. Poland was divided between Germany and the Soviet Union under the Molotov–Ribbentrop Pact. In 1940, the Soviet Union annexed the Baltic states and parts of Finland and Romania. After the fall of France in June 1940, the war continued mainly between Germany, now assisted by Fascist Italy, and the British Empire, with fighting in the Balkans, Mediterranean, and Middle East, the aerial Battle of Britain and the Blitz, and the naval Battle of the Atlantic. Through campaigns and treaties, Germany gained control of much of continental Europe and formed the Axis alliance with Italy, Japan, and other countries. In June 1941, Germany invaded the Soviet Union, opening the Eastern Front and initially making large territorial gains.