The 1940s are remembered today as the decade of war. Even when the treaties were signed and the fighting stopped, the aftermath of the Second World War still dominated the globe, and its repercussions took many nations decades to recover. For others, it sparked a slew of infighting, civil war, and independence. Here are 7 historical events that took place in the 1940s (1940-1949).
The Nazi invasion of Europe (May – October 1940)
Having signed their pact with the Soviet Union and officially started the Second World War by invading Poland the previous year, Nazi Germany continued to throw their weight around by making quick work of other European nations through 1940. Emboldened by a strong Eastern ally, Hitler’s Germany invaded France, the Netherlands, Norway, and Denmark, occupying much of the continent. However, their attempts to knock Britain out of the war and set up for a land invasion proved their first stumbling block. The Blitz rocked Britain, turning many cities into rubble. Still, their inability to knock them out of the war early proved detrimental, as British intelligence became one of the biggest thorns in their side.
The Nazi invasion of the Soviet Union begins (June 1941)

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Perhaps Hitler’s most significant mistake in the Second World War was turning on Joseph Stalin. The betrayal of their Molotov-Ribbentrop Pact created an additional front, lost them protection in the east, and dragged the Soviet Union onto the Allies’ side. Beginning their Soviet campaign on the 22nd of June 1941, their hopes for a quick routing of Russia were first scuppered at the capital during the Siege of Leningrad – possibly the bloodiest siege in human history, followed by another bloody battle, the Battle of Stalingrad. Soviet forces were thoroughly outmatched, but the perseverance of their soldiers and fierce Russian winters proved to be Hitler’s undoing. Nazi Germany would be bogged down in the east for the rest of the war.
The Japanese attack on Pearl Harbour (December 1941)
While Nazi Germany opened the eastern front, the Allies struggled to keep them at bay in the west. Across the Atlantic, America was reluctant to get involved, but that all changed at the Pearl Harbour naval base in Honolulu early in the morning of the 7th December 1941. Tensions had been high between the US and Japan for decades, with the latter eager to keep America out of the war and away from their own imperial ambitions. It seemed a matter of time before this led to war, which led to the Japanese launching a surprise attack to try and land a crippling pre-emptive blow. 353 Japanese aircraft bombarded and destroyed four of eight US battleships, killing 2,403 Americans and causing President Franklin D. Roosevelt to respond the next day with a declaration of war against Japan. Days later, Germany and Italy declared on the US, and they were officially involved.
D-Day Normandy landings (June 1944)

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After a monumental meeting of minds at the Tehran Conference in the last months of 1943, Roosevelt, Churchill, and Stalin all signed off on Operation Overlord: the codename for the full-scale invasion of German-occupied Western Europe. Around 160,000 troops crossed the English Channel on the 6th of June 1944 in the largest seaborne invasion in history. Thousands lost their lives on both sides, and initial objectives to take nearby towns upon arrival failed, but five beachheads were established, allowing them to push further inland in the coming days. The D-Day landings were a tremendous success in the larger scope of the conflict. In just under three months, the Allies had overwhelmed the Nazis in France and permanently turned the tide of the war against Hitler.
The end of the Second World War (May-September 1945)
With defeat seeming inevitable, the execution of Italian dictator Mussolini and the suicide of Hitler within several days of each other in May brought an end to the war in Europe after almost six years. The war in the east would continue for a few months longer, but when the US dropped atomic bombs on Hiroshima and Nagasaki in early August, this served as the exclamation point on the allied victory, and Japan quickly surrendered. With treaties drawn up, the Second World War was officially over, but across the world, the fallout was becoming apparent in its aftermath. Germany was split between West and East, and Korea was divided between North and South. At the same time, the war continued in China with its resumed civil war, in the Arab world over the creation of the Israel state, and between India and Pakistan after both gained independence and warred over territory. Europe, meanwhile, would take decades to recover financially.
The Nuremberg Trials (November 1945 – October 1946)

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The true horrors of the Nazi atrocities emerged in the aftermath of the war, and the Nuremberg Trials were arranged to judge, sentence, and condemn the accused. France, the United States, Britain, and the Soviet Union each provided judges and prosecutors as the first trial began on the 19th of November, 1945. Twenty-four members of Nazi leadership took to the stand, with witnesses ranging from former SS officers to Holocaust survivors. The questioning and gathering of evidence continued until the 30th of September 1946, when the verdicts and sentencing began. Taking just two days, of the twenty-four accused, all but five either received long prison sentences or were sentenced to death, with the latter meeting their fates on the 16th of October. The success of these trials paved the way for an international criminal court, the Geneva Convention, and principles of wartime conduct to avoid future atrocities.
The People’s Republic of China is established (October 1949)
Emerging from its long war with Japan, China became one of the conflict’s biggest victors. But immediately after, the Republic was ravaged financially and in-fighting between rival groups and ideologies. The Chinese Civil War actually began way back in 1927 but was temporarily halted when the Japanese invaded ten years later. With the Japanese surrender and their troops withdrawn, the uneasy alliance between the Nationalist and Communist Parties was swiftly resumed. By the end of the 1940s, the Soviet-backed Mao Zedong’s CCP defeated the Kuomintang’s Chiang Kai-Shek, who fled to Taiwan, taking the Republic of China with him. The mainland was declared the People’s Republic of China by Mao on the 1st October 1949, and he would go on to reign as dictator. During the civil war, millions lost their lives, but when it was over, and Mao tightened his grip, millions more would follow.
If you enjoyed this article on historical events in the 1940s, be sure to check out 1900s – 7 Historical Events that happened in the 1900s (1900-1909)