The Second World War, a cataclysmic conflict that engulfed the globe from 1939 to 1945, remains the deadliest and most widespread war in human history. Arising from a complex interplay of unresolved grievances from the First World War, aggressive expansionist ideologies, and the failure of international diplomacy, the war pitted the Allied powers against the Axis nations in a struggle that would reshape the political landscape and leave an indelible mark on the 20th century. The following chronology meticulously details the key events, from the pre-war tensions that ignited the conflagration to the final acts of surrender that brought six years of unprecedented global conflict to a close.
Causes of World War II (Pre-War Events)
1919: The Treaty of Versailles, signed at the cessation of the Great War, imposed exceptionally stringent conditions upon Germany. These included the forfeiture of significant territories, the obligation to pay hefty financial reparations to the Allied nations, severe limitations on the size and scope of its armed forces, and the infamous “war guilt clause,” which compelled Germany to accept sole responsibility for initiating the conflict. This punitive treaty cultivated deep-seated resentment and economic hardship within German society, creating fertile ground for extremist ideologies such as Nazism to take root and flourish.
1931: Japan invades Manchuria, a resource-rich province in north-eastern China, establishing the puppet state of Manchukuo under its control. This act of blatant aggression clearly demonstrated Japan’s expansionist ambitions in Asia and starkly illustrated the feebleness of the League of Nations in enforcing international law and preventing military conquest. It represented a significant stride towards a broader conflict in the Pacific theatre.
1933: Adolf Hitler and the Nazi Party seize power in Germany, capitalising on widespread economic malaise, political instability, and fervent nationalist sentiments inflamed by the Treaty of Versailles. Hitler propagated a radical ideology centred on ultranationalism, the doctrine of racial supremacy (with particular virulence directed towards Jewish people), and the necessity for territorial expansion (“Lebensraum,” or living space). Germany also withdraws from the League of Nations, a symbolic act signifying its intention to disregard international agreements and pursue its own aggressive agenda.
1935: Italy invades Abyssinia (modern-day Ethiopia), an independent nation in Africa, driven by aspirations of colonial expansion and the pursuit of national prestige under its Fascist leader, Benito Mussolini. This act of aggression, despite condemnation from the League of Nations, further exposed the organisation’s ineffectualness. Concurrently, Germany openly rearms, significantly building up its military strength in direct contravention of the Treaty of Versailles, a blatant violation that elicited little concrete opposition from other European powers.
1936: Germany remilitarises the Rhineland, a strategically crucial region bordering France, once again flouting the terms of the Treaty of Versailles. This audacious move was met with merely diplomatic protests from Britain and France, further emboldening Hitler in his expansionist designs. The Rome-Berlin Axis is formed between Germany and Italy, a pact of cooperation and mutual support solidifying the alliance between the two fascist regimes. Japan joins the Anti-Comintern Pact with Germany, an agreement ostensibly aimed at countering the spread of international communism, further cementing the emerging Axis alignment. The Spanish Civil War erupts, a brutal internal conflict between the Nationalist forces (heavily supported by Germany and Italy) and the Republican forces (backed by the Soviet Union and international volunteers). This war served as a proving ground for Axis military tactics and weaponry.
1937: Japan invades China proper, escalating the Second Sino-Japanese War into a full-blown conflict characterised by extreme brutality and widespread atrocities, most notably the Nanking Massacre. This full-scale invasion underscored Japan’s relentless aggression in Asia and further strained already tense international relations.
1938: Germany annexes Austria (the Anschluss), forcibly uniting the two German-speaking nations in direct violation of the Treaty of Versailles, which had explicitly forbidden such a union. This was a significant step in realising Hitler’s expansionist aims. The Munich Agreement witnessed Britain and France adopting a policy of appeasement towards Hitler, permitting Germany to annex the Sudetenland, a border region of Czechoslovakia with a substantial German-speaking population, in exchange for Hitler’s promise of no further territorial demands. This policy of appeasement is now widely regarded as a catastrophic misjudgement that only served to embolden Hitler.
March 1939: Germany, having secured the Sudetenland through diplomatic coercion, proceeds to occupy the remainder of Czechoslovakia, unequivocally demonstrating the futility of the Munich Agreement and revealing Hitler’s true intentions of territorial conquest extending far beyond the unification of German-speaking peoples. This act finally convinced Britain and France that appeasement had failed irrevocably, leading them to issue a guarantee of support to Poland in the event of German aggression.
August 1939: The Nazi-Soviet Pact (Molotov-Ribbentrop Pact) is signed, a startling non-aggression treaty between the ideologically opposed Nazi Germany and the communist Soviet Union. This pact contained a secret protocol outlining the division of Eastern Europe into spheres of influence, with Poland slated for partition between the two powers. This agreement effectively neutralised the threat of a two-front war for Germany and cleared the path for the imminent invasion of Poland.
The War Begins (1939-1941)
September 1, 1939: Germany invades Poland, employing the innovative “Blitzkrieg” (lightning war) tactics of rapid armoured advances supported by overwhelming air power. This invasion, following fabricated “Polish attacks” on German border posts as a pretext, prompted declarations of war by both France and the United Kingdom on September 3rd, officially marking the commencement of World War II.
September 17, 1939: Following the swift and devastating German advance across Poland and the rapid collapse of Polish resistance in the west, the Soviet Union invades Poland from the east, fulfilling its obligations under the secret protocol of the Nazi-Soviet Pact and occupying the eastern territories. Poland was swiftly partitioned between Nazi Germany and the Soviet Union, effectively ceasing to exist as an independent state.
November 30, 1939 – March 13, 1940: The Winter War between the Soviet Union and Finland commenced with a Soviet invasion of its smaller neighbour. Despite a valiant and surprisingly effective Finnish defence, the numerically superior Soviet forces eventually prevailed, culminating in the Moscow Peace Treaty, which compelled Finland to cede significant territories to the Soviet Union.
April 9 – June 9, 1940: Germany invades Denmark and Norway in Operation Weserübung. Denmark fell with remarkable speed, while Norway, although receiving some support from British and French forces, offered more sustained resistance but ultimately succumbed to the superior German invasion, securing vital naval bases and strategic resources for the German war effort.
May 10 – June 22, 1940: The Battle of France witnessed Germany launching a devastating offensive through the heavily wooded Ardennes region, effectively bypassing the heavily fortified but static Maginot Line. German panzer divisions executed a rapid advance, outmanoeuvring the Allied forces and leading to the swift and comprehensive defeat of France. British Expeditionary Force troops were forced into a desperate evacuation from Dunkirk, and France was subsequently divided into a German-occupied zone and the Vichy regime, a collaborationist government in the south.
July 10 – October 31, 1940: The Battle of Britain was a crucial aerial campaign waged by the German Luftwaffe against the United Kingdom. Germany’s objective was to achieve air superiority over Britain as a necessary prerequisite for a potential seaborne invasion (Operation Sea Lion). The Royal Air Force (RAF), although significantly outnumbered, successfully defended British airspace, inflicting substantial losses on the Luftwaffe and ultimately forcing Hitler to postpone indefinitely and eventually abandon his invasion plans.
September 27, 1940: The Tripartite Pact is signed by Germany, Italy, and Japan, formally establishing the Axis alliance. This pact committed the signatory powers to mutual support and recognised their respective spheres of influence in Europe and Asia, solidifying their coalition against the Allied powers.
October 28, 1940 – April 1941: The Greco-Italian War began with Italy’s ill-conceived invasion of Greece. However, the poorly equipped and inadequately prepared Italian forces were met with unexpectedly fierce and effective Greek resistance, resulting in the Italians being pushed back into neighbouring Albania. This unforeseen setback for Mussolini’s regime necessitated German intervention in the Balkans to secure their southern flank.
February – May 1941: The North African Campaign intensifies significantly with the arrival of substantial German forces, the Afrika Korps, under the command of the highly skilled and tactically brilliant General Erwin Rommel. Rommel’s initial offensives achieved considerable success, pushing the British forces back across Libya and deep into Egypt, posing a grave threat to the strategically vital Suez Canal.
April 6 – May 1941: Germany invades Yugoslavia and Greece in Operations Marita and Unternehmen 25, respectively, actions undertaken partly to secure the Balkan flank before the planned invasion of the Soviet Union (Operation Barbarossa). Yugoslavia swiftly succumbed to the overwhelming German onslaught, and Greece, despite receiving limited British support, was also eventually overrun, further consolidating Axis control in the region.
June 22, 1941: Germany launches Operation Barbarossa, the invasion of the Soviet Union, the largest military operation in the history of warfare. This colossal offensive aimed to achieve a swift conquest of vast Soviet territories and their crucial resources. Initial German advances were remarkably rapid and devastating, catching the Soviet Red Army largely unprepared and resulting in immense casualties and significant territorial losses for the USSR.
December 7, 1941: Japan launches a surprise attack on Pearl Harbor, the principal United States naval base in the Pacific, with a devastating aerial assault. This audacious attack crippled a significant portion of the US Pacific Fleet and precipitated the United States’ declaration of war on Japan the following day, formally drawing America into World War II.
December 11, 1941: Following the United States’ declaration of war on Japan, both Germany and Italy declare war on the United States, fulfilling their obligations under the Tripartite Pact. This act transformed the existing European and Pacific conflicts into a truly global war, encompassing the world’s major powers.
Escalation and Global Conflict (1942-1943)
January 20, 1942: The Wannsee Conference was convened in a suburb of Berlin, where senior Nazi officials gathered to formalise the “Final Solution to the Jewish Question” (Endlösung der Judenfrage), the meticulously planned and systematic genocide of European Jews. This chilling meeting marked a horrific and irreversible escalation of the Holocaust.
May 4-8, 1942: The Battle of the Coral Sea was a pivotal naval engagement in the Pacific between the United States and Japan. While tactically inconclusive in terms of ships sunk, it represented a significant strategic victory for the Allies as it successfully halted the Japanese advance towards Australia and underscored the critical importance of aircraft carriers in modern naval warfare.
June 4-7, 1942: The Battle of Midway proved to be a decisive naval victory for the United States against the Imperial Japanese Navy. American codebreakers had successfully deciphered Japanese naval codes, providing advance warning of the attack and allowing the US Navy to lay a strategic ambush. The ensuing battle resulted in the destruction of four Japanese fleet carriers, a catastrophic loss that severely crippled Japan’s offensive capabilities in the Pacific and marked a crucial turning point in the Pacific War, shifting the strategic initiative to the Allies.
August 23, 1942 – February 2, 1943: The Battle of Stalingrad was an exceptionally brutal and strategically vital battle fought on the Eastern Front. German forces engaged in a fierce and protracted struggle to capture the strategically important city on the Volga River. However, the determined Soviet Red Army mounted a tenacious and ultimately successful defence, culminating in the encirclement and eventual surrender of the entire German Sixth Army. This catastrophic defeat represented a major turning point in the war on the Eastern Front, effectively halting the seemingly unstoppable German advance and initiating the sustained Soviet push westward.
October 23 – November 5, 1942: The Second Battle of El Alamein was a decisive victory for the British Eighth Army, under the command of General Bernard Montgomery, against the German Afrika Korps and Italian forces in North Africa. This pivotal battle shattered the stalemate in the Western Desert, forcing Rommel’s forces into a long and ultimately terminal retreat westward across Libya and significantly weakening Axis presence in North Africa.
November 8, 1942: Operation Torch involved the Allied landings in French North Africa (specifically in Morocco and Algeria). This major amphibious operation, involving American and British forces, aimed to dislodge Axis forces from North Africa by launching an attack from the west. It ultimately led to the encirclement and surrender of the remaining German and Italian troops in Tunisia in May 1943.
July 5 – August 23, 1943: The Battle of Kursk stands as the largest tank battle in the history of warfare, representing the last major German offensive on the Eastern Front. The German Wehrmacht launched a large-scale armoured assault aimed at eliminating a substantial Soviet salient. Despite initial German advances, the well-prepared and heavily fortified Soviet defences, coupled with powerful counterattacks, blunted the German offensive, resulting in significant losses for the German armoured divisions and definitively ending their ability to launch large-scale offensives on the Eastern Front.
July 10 – August 17, 1943: The Allied invasion of Sicily (Operation Husky) marked the first significant Allied landing on Axis-held European territory. The successful campaign, characterised by swift Allied advances, led to the rapid capture of the island and played a significant role in the subsequent downfall of Benito Mussolini’s regime in Italy.
September 3, 1943: Following the Allied invasion of Sicily and mounting internal political opposition, Italy surrenders unconditionally to the Allied forces. However, German forces stationed in Italy continued to offer fierce resistance, leading to a protracted and bloody campaign as the Allies fought their way up the Italian peninsula.
The Tide Turns (1944)
January 17 – May 18, 1944: The Battle of Monte Cassino comprised a series of four arduous and costly Allied assaults against the heavily fortified German Gustav Line, which was anchored around the historically significant Monte Cassino abbey in Italy. The challenging mountainous terrain and tenacious German resistance resulted in months of intense fighting and substantial Allied casualties before the German defensive lines were finally breached, opening the path to Rome.
June 6, 1944: D-Day (Operation Overlord) was the momentous Allied landings in Normandy, France, representing the largest amphibious invasion in military history. American, British, Canadian, and other Allied forces landed on five designated beaches, facing formidable German coastal defences. Despite incurring heavy casualties, the Allies successfully established a crucial beachhead, thereby opening the long-awaited Western Front against Nazi Germany and marking a decisive turning point in the European theatre.
June 22 – August 19, 1944: Operation Bagration was a colossal and highly successful Soviet offensive on the Eastern Front, specifically targeting the German Army Group Centre in Byelorussia (modern-day Belarus). This meticulously planned offensive employed deception and overwhelming numerical and material superiority, shattering the German front lines and inflicting catastrophic losses on the Wehrmacht. It paved the way for a rapid Soviet advance into Poland and towards the heart of Germany.
July 20, 1944: The July Plot was a significant but ultimately unsuccessful attempt by a group of disillusioned German Wehrmacht officers to assassinate Adolf Hitler. Colonel Claus von Stauffenberg planted a bomb at Hitler’s headquarters in East Prussia, but Hitler miraculously survived the explosion. The subsequent brutal crackdown by the Nazi regime led to the arrest and execution of numerous individuals involved in the German resistance movement.
August 15, 1944: Operation Dragoon involved the Allied landings in Southern France, along the French Riviera. This second major Allied amphibious landing in France swiftly secured vital ports and facilitated the rapid advance of Allied forces northwards through the Rhone Valley, eventually linking up with the forces that had landed in Normandy and further liberating French territory from German occupation.
August 25, 1944: Paris is liberated by the Allied forces, a momentous symbolic and strategic victory. The Free French Forces played a prominent role in the liberation of the French capital, effectively ending the German occupation and restoring French sovereignty over its capital city.
December 16, 1944 – January 25, 1945: The Battle of the Bulge represented Germany’s last major offensive on the Western Front. Exploiting a relatively thinly defended section of the Allied lines in the Ardennes forest during the winter, the Germans launched a surprise counter-offensive with the aim of splitting the Allied armies and recapturing the crucial port of Antwerp. Despite achieving initial surprise and creating a significant bulge in the Allied lines, the Allied forces, particularly the tenacious American defenders at Bastogne, held firm, and substantial reinforcements eventually pushed back the German offensive, effectively exhausting Germany’s remaining offensive capabilities in the West.
The End of the War (1945)
January 12 – May 9, 1945: The Vistula–Oder Offensive and the East Prussian Offensive were massive and relentless Soviet offensives on the Eastern Front. These powerful drives propelled the Red Army deep into German territory, overwhelming the severely depleted German forces and resulting in immense destruction and the displacement of millions of German civilians.
February 4-11, 1945: The Yalta Conference brought together the “Big Three” Allied leaders: Winston Churchill (Prime Minister of the United Kingdom), Franklin D. Roosevelt (President of the United States), and Joseph Stalin (leader of the Soviet Union). They convened to discuss the post-war reorganisation of Europe, the future of a defeated Germany, and the Soviet Union’s commitment to entering the war against Japan following Germany’s surrender.
February 19 – March 26, 1945: The Battle of Iwo Jima was a fiercely contested and exceptionally bloody battle for a small but strategically vital Japanese island in the Pacific. The US Marines faced fanatical Japanese resistance who were deeply entrenched in heavily fortified underground positions, resulting in extremely high casualties on both sides. Securing Iwo Jima provided the United States with a crucial airbase for long-range bombing raids against mainland Japan.
April 1 – June 22, 1945: The Battle of Okinawa was another intensely fought and exceptionally costly battle in the Pacific, this time for a large island located relatively close to the Japanese mainland. The prolonged and brutal fighting against determined Japanese defenders, including numerous kamikaze attacks, provided a grim foretaste of the potential casualties that would be incurred in a full-scale invasion of the Japanese home islands.
April 16 – May 2, 1945: The Battle of Berlin was the final major and intensely fought battle in the European theatre, as the Soviet Red Army fought its way into the heart of the German capital. Fierce urban warfare, characterised by brutal street-to-street fighting, resulted in immense destruction and heavy casualties on both sides. The battle culminated in the fall of Berlin to the Soviet forces and the suicide of Adolf Hitler in his bunker.
April 30, 1945: Facing the inevitable capture of Berlin by the advancing Soviet forces and the complete collapse of his regime, Adolf Hitler commits suicide in his underground bunker, along with his wife Eva Braun. His death marked the definitive end of the Nazi leadership and paved the way for Germany’s unconditional surrender.
May 7, 1945: Germany unconditionally surrenders to the Western Allies in Reims, France. The instrument of surrender was signed by General Alfred Jodl, Chief of Staff of the Wehrmacht, and applied to all German forces under his command in the West.
May 8, 1945: Victory in Europe Day (V-E Day) is celebrated across the Allied nations, marking the formal end of the war in Europe. This followed the signing of a more comprehensive and formal surrender document in Berlin to representatives of both the Western Allies and the Soviet Union.
July 17 – August 2, 1945: The Potsdam Conference brought together the remaining “Big Three” Allied leaders: Harry S. Truman (President of the United States), Clement Attlee (Prime Minister of the United Kingdom, replacing Churchill during the conference), and Joseph Stalin (leader of the Soviet Union). They convened to discuss the post-war order in Europe, the final stages of the war against Japan, and issued the Potsdam Declaration, demanding Japan’s unconditional surrender.
August 6, 1945: The United States drops an atomic bomb on Hiroshima, Japan, a horrific act of unprecedented destructive power that resulted in the immediate deaths of tens of thousands of civilians and widespread devastation of the city. This drastic measure was taken with the aim of forcing Japan’s swift surrender and avoiding a potentially catastrophic invasion of the Japanese mainland.
August 9, 1945: The United States drops a second atomic bomb on Nagasaki, Japan, causing further immense destruction and a staggering loss of civilian life. Simultaneously, the Soviet Union declares war on Japan and launches a full-scale invasion of Manchuria, rapidly overwhelming the Japanese Kwantung Army in a decisive land offensive.
August 15, 1945: Victory over Japan Day (V-J Day) is announced, following Japan’s formal acceptance of the terms of the Potsdam Declaration and its unconditional surrender to the Allied powers. Emperor Hirohito’s unprecedented radio address to the Japanese nation informed them of the decision to end the war.
September 2, 1945: The formal instrument of surrender is signed by representatives of Japan and the Allied powers on board the US battleship USS Missouri in Tokyo Bay, officially bringing World War II to its definitive conclusion.
The cessation of hostilities in September 1945 marked not only the end of a devastating global war but also the dawn of a new era. The immense human cost, the reshaping of national borders, the rise of new superpowers, and the establishment of international organisations like the United Nations were all profound consequences of the conflict detailed in this chronology. The Second World War serves as a stark reminder of the catastrophic potential of unchecked aggression and the enduring importance of international cooperation in striving for lasting peace.