Operation Barbarossa was the invasion of the Soviet Union by Nazi Germany and many of its Axis allies, starting on Sunday, 22 June 1941, during World War II. It was the largest and costliest land offensive in human history, with around 10 million combatants taking part, and over 8 million casualties by the end of the operation.
World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all the world's countries—including all the great powers—participated, with many investing all available economic, industrial, and scientific capabilities in pursuit of total war, blurring the distinction between military and civilian resources. Tanks and aircraft played major roles, with the latter enabling the strategic bombing of population centres and delivery of the only two nuclear weapons ever used in war. World War II was the deadliest conflict in history, resulting in 70 to 85 million fatalities, more than half of which were civilians. Millions died in genocides, including the Holocaust of European Jews, and by massacres, starvation, and disease. Following the Allied powers' victory, Germany, Austria, Japan, and Korea were occupied, and war crimes tribunals were conducted against German and Japanese leaders.
The Axis powers, originally called the Rome–Berlin Axis and also Rome–Berlin–Tokyo Axis, was a military coalition that initiated World War II and fought against the Allies. Its principal members were Nazi Germany, Fascist Italy and the Empire of Japan. The Axis were united in their far-right positions and general opposition to the Allies, but otherwise lacked comparable coordination and ideological cohesion.
The Tehran Conference was a strategy meeting of the Allies of World War II, held between Joseph Stalin, Franklin D. Roosevelt, and Winston Churchill from 28 November to 1 December 1943. It was the first of the Allied World War II conferences involving the "Big Three" and took place at the Soviet embassy in Tehran just over a year after the Anglo-Soviet invasion of Iran. The meeting occurred shortly after the Cairo Conference was held in Egypt for a discussion between the United States, the United Kingdom, and China from 22 to 26 November 1943. The Big Three would not meet again until 1945, when the Yalta Conference was held in Crimea from 4 to 11 February and the Potsdam Conference was held in Allied-occupied Germany from 17 July to August 2.
The Invasion of Poland, also known as the September Campaign, Polish Campaign, and Polish Defensive War of 1939, was a joint attack on the Republic of Poland by Nazi Germany, the Slovak Republic, and the Soviet Union, which marked the beginning of World War II. The German invasion began on 1 September 1939, one week after the signing of the Molotov–Ribbentrop Pact between Germany and the Soviet Union, and one day after the Supreme Soviet of the Soviet Union had approved the pact. One of the aims of the invasion was to divide Polish territory at the end of the operation; Poland was to cease to exist as a country and all Poles were to be exterminated. The Soviets invaded Poland on 17 September. The campaign ended on 6 October with Germany and the Soviet Union dividing and annexing the whole of Poland under the terms of the German–Soviet Frontier Treaty. The invasion is also known in Poland as the September campaign or 1939 defensive war and known in Germany as the Poland campaign.
Franz Halder was a German general and the chief of staff of the Army High Command (OKH) in Nazi Germany from 1938 until September 1942. During World War II, he directed the planning and implementation of Operation Barbarossa, the 1941 invasion of the Soviet Union. Halder became instrumental in the radicalisation of warfare on the Eastern Front. He had his staff draft both the Commissar Order and the Barbarossa Decree that allowed German soldiers to execute Soviet citizens for any reason without fear of later prosecution, leading to numerous war crimes and atrocities during the campaign. After the war, he had a decisive role in the development of the myth of the clean Wehrmacht.
The German invasion of Greece, also known as the Battle of Greece or Operation Marita, were the attacks on Greece by Italy and Germany 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 Balkans Campaign of the Axis powers and their associates.
Almost every country in the world participated in World War II. Most were neutral at the beginning, but only a relative few nations remained neutral to the end. The Second World War pitted two alliances against each other, the Axis powers and the Allied powers. It is estimated that 74 million people died, with estimates ranging from 40 million to 90 million dead. The main Axis powers were Nazi Germany, the Empire of Japan, and the Kingdom of Italy; while the United Kingdom, the United States, the Soviet Union and China were the "Big Four" Allied powers.
The Mediterranean and Middle East Theatre was a major theatre of operations during the Second World War. The vast size of the Mediterranean and Middle East theatre saw interconnected naval, land, and air campaigns fought for control of the Mediterranean, North Africa, the Horn of Africa, the Middle East and Southern Europe. The fighting started from 10 June 1940, when Italy declared war on United Kingdom and France, until 2 May 1945 when all Axis forces in Italy surrendered. However, fighting would continue in Greece – where British troops had been dispatched to aid the Greek government – during the early stages of the Greek Civil War.
The Allies, formally referred to as the United Nations from 1942, were an international military coalition formed during World War II (1939–1945) to oppose the Axis powers. Its principal members by the end of 1941 were the "Big Four" – the United Kingdom, United States, Soviet Union, and China.
The Reichskommissariat Kaukasien, also spelled Kaukasus, was the theoretical political division and planned civilian occupation regime of Germany in the occupied territories of the Caucasus region during World War II. Unlike the other four planned Reichskommissariats, within the borders of the proposed Caucasus Reichskommissariat experiments were to be conducted for various forms of autonomy for "indigenous groups".
The history of Bulgaria during World War II encompasses an initial period of neutrality until 1 March 1941, a period of alliance with the Axis Powers until 8 September 1944, and a period of alignment with the Allies in the final year of the war. With German consent, Bulgarian military forces occupied parts of the Kingdoms of Greece and Yugoslavia which Bulgarian irredentism claimed on the basis of the 1878 Treaty of San Stefano. Bulgaria resisted Axis pressure to join the war against the Soviet Union, which began on 22 June 1941, but did declare war on Britain and the United States on 13 December 1941. The Red Army entered Bulgaria on 8 September 1944; Bulgaria declared war on Germany the next day.
The Third Washington Conference was held in Washington, D.C from May 12 to May 25, 1943. It was a World War II strategic meeting between the heads of government of the United Kingdom and the United States. It was the third conference of the 20th century, but the second conference that took place during the US involvement in the Second World War. The delegations were headed by Winston Churchill and Franklin D. Roosevelt, respectively.
The neutral powers were countries that remained neutral during World War II. Some of these countries had large colonies abroad or had great economic power. Spain had just been through its civil war, which ended on 1 April 1939 —a war that involved several countries that subsequently participated in World War II.
The German Army was the land forces component of the Wehrmacht, the regular armed forces of Nazi Germany, from 1935 until it effectively ceased to exist in 1945 and then was formally dissolved in August 1946. During World War II, a total of about 13.6 million soldiers served in the German Army. Army personnel were made up of volunteers and conscripts.
The Soviet offensive plans controversy was a debate among historians in the late 20th and early 21st centuries as to whether Joseph Stalin had planned to launch an attack against Nazi Germany in the summer of 1941. The controversy began with Soviet defector Viktor Suvorov with his 1988 book Icebreaker: Who started the Second World War? In it, he claimed that Stalin used Nazi Germany as a proxy to attack Europe.
The Yugoslav coup d'état took place on 27 March 1941 in Belgrade, Kingdom of Yugoslavia, when the regency led by Prince Paul of Yugoslavia was overthrown and King Peter II fully assumed monarchical powers. The coup was planned and conducted by a group of pro-Western Serbian-nationalist Royal Yugoslav Air Force officers formally led by the Air Force commander, General Dušan Simović, who had been associated with several putsch plots from 1938 onwards. Brigadier General of Military Aviation Borivoje Mirković, Major Živan Knežević of the Yugoslav Royal Guards, and his brother Radoje Knežević were the main organisers in the overthrow of the government. In addition to Radoje Knežević, some other civilian leaders were probably aware of the takeover before it was launched and moved to support it once it occurred, but they were not among the organisers. Peter II himself was surprised by the coup, and heard of the declaration of his coming-of-age for the first time on the radio.
The diplomatic history of World War II includes the major foreign policies and interactions inside the opposing coalitions, the Allies of World War II and the Axis powers, between 1939 and 1945.
