Chapter 4: The Second World War (1939–1945)

The Second World War (1939–1945) was the deadliest conflict in human history, involving more than 30 countries and resulting in an estimated 7–8 crore deaths. It arose directly from the unresolved grievances of WWI, the rise of totalitarian regimes, and the failure of the international community to maintain peace.

Quick Facts Duration: 1 September 1939 – 2 September 1945 | Allied Powers: UK, France, USSR (from 1941), USA (from 1941), China | Axis Powers: Germany, Italy, Japan

1. Causes of the Second World War

Dissatisfaction with the Treaty of Versailles (1919)

The Treaty of Versailles was seen by Germans as a "Diktat" (dictated peace) — imposed without negotiation.
The War Guilt Clause forced Germany to accept full blame; crippling reparations (£6.6 billion) destroyed the German economy.
Germany lost 13% of its territory and 10% of its population — Alsace-Lorraine, the Polish Corridor, all overseas colonies.
Military restrictions humiliated German pride — army limited to 1,00,000; no air force; Rhineland demilitarized.
This humiliation created deep resentment, fuelled by extremist politicians like Hitler who exploited German anger to rise to power with a promise to undo Versailles.

Rise of Fascism and Nazism

Mussolini in Italy (1922) and Hitler in Germany (1933) came to power on platforms of aggressive nationalism and expansionism.
Hitler began violating the Treaty of Versailles openly — reintroduced conscription (1935), remilitarized the Rhineland (1936), annexed Austria — Anschluss (1938), then Sudetenland (1938), then all of Czechoslovakia (1939).
Mussolini invaded Abyssinia (Ethiopia) in 1935–36; both dictators supported Franco in the Spanish Civil War (1936–39) — testing their weapons.
Rome-Berlin-Tokyo Axis (1936–37): Germany, Italy, and Japan formed a military alliance that threatened world peace.

Policy of Appeasement

Britain and France adopted a policy of giving in to Hitler's demands hoping to avoid a new world war. This policy was called Appeasement.
Munich Agreement (September 1938): British PM Neville Chamberlain and French PM Daladier met Hitler and Mussolini in Munich. They allowed Hitler to annex the Sudetenland (Czech region) without Czech consultation. Chamberlain returned proclaiming "peace for our time."
Appeasement failed because it encouraged Hitler to make further demands — he took all of Czechoslovakia in March 1939.
Winston Churchill criticized it: "An appeaser is one who feeds the crocodile, hoping it will eat him last."

Japanese Invasion of China

Manchuria (1931): Japan invaded and occupied the Chinese province of Manchuria, setting up the puppet state of Manchukuo. The League of Nations sent the Lytton Commission — Japan simply ignored the report and left the League (1933). This showed that the League had no teeth to stop aggressors.
Marco Polo Bridge Incident (July 1937): Japan launched a full-scale invasion of China — the Second Sino-Japanese War began. Japan captured Shanghai and Nanking.
Nanjing Massacre (December 1937): Japanese troops committed horrific atrocities in Nanking — approximately 3 lakh Chinese civilians and soldiers were massacred. It shocked the world.
Japan's aggression in Asia was part of its dream of a Greater East Asia Co-Prosperity Sphere — dominating all of Asia and the Pacific. Japan, Germany, and Italy signed the Tripartite Pact (1940) forming the full Axis alliance.
Japan's aggression showed the failure of the League of Nations and emboldened Hitler and Mussolini to pursue their own ambitions.

Failure of the League of Nations

The League failed to stop Japan in Manchuria (1931), Italy in Abyssinia (1935), or Germany in the Rhineland (1936).
The USA had never joined; Germany was initially excluded; the USSR joined only in 1934.
The League had no standing army and could not enforce its resolutions effectively.

Immediate Cause Hitler's Invasion of Poland — 1 September 1939:
After signing the Nazi-Soviet Non-Aggression Pact (23 August 1939) — secretly dividing Eastern Europe — Hitler invaded Poland using Blitzkrieg (lightning war) tactics: fast-moving tanks, aircraft, and motorized infantry striking simultaneously. Britain and France had guaranteed Polish independence and declared war on Germany on 3 September 1939. The Second World War had begun.

2. Key Events of the War

Sep 1939

Germany invades Poland. Britain and France declare war. WWII begins.

May–Jun 1940

Fall of France. Dunkirk evacuation — 3,38,000 Allied troops rescued from beaches. Germany occupies Paris.

Jul–Oct 1940

Battle of Britain — Luftwaffe bombs Britain; RAF resists heroically. Britain survives under Churchill's leadership.

Jun 1941

Operation Barbarossa — Germany invades USSR, breaking the Nazi-Soviet Pact. Eastern Front becomes the largest and bloodiest theatre of the war.

7 Dec 1941

Japan launches surprise attack on the US naval base at Pearl Harbor, Hawaii. Over 2,400 Americans killed; 18 warships sunk or damaged. USA declares war on Japan; Germany and Italy declare war on USA.

1942–43

Battle of Stalingrad — USSR defeats Germany. Germany's 6th Army surrenders. Turning point of WWII — Germany never recovered offensively.

6 Jun 1944

D-Day — Operation Overlord — Allied forces (USA, UK, Canada) land on the beaches of Normandy, France. Liberation of Western Europe begins.

30 Apr 1945

Hitler commits suicide in his Berlin bunker. Eva Braun dies with him.

8 May 1945

V-E Day (Victory in Europe) — Germany surrenders unconditionally. War in Europe ends.

6 Aug 1945

Atomic bomb "Little Boy" dropped on Hiroshima — 70,000–80,000 killed instantly; entire city flattened.

9 Aug 1945

Atomic bomb "Fat Man" dropped on Nagasaki — approximately 40,000 killed instantly.

2 Sep 1945

Japan surrenders aboard USS Missouri in Tokyo Bay. V-J Day — WWII officially ends.

3. Pearl Harbor — USA Enters the War

On 7 December 1941, Japan launched a devastating surprise attack on the US Pacific Fleet at Pearl Harbor, Hawaii.
Over 2,400 Americans were killed; 1,178 wounded; 8 battleships, 3 destroyers, and 188 aircraft destroyed or damaged.
US President Franklin D. Roosevelt declared 7 December "a date which will live in infamy" and asked Congress to declare war on Japan on 8 December 1941.
The USA's entry was decisive — its industrial power, manpower, and resources ultimately won the war for the Allied Powers.

4. Atomic Bombs — Hiroshima and Nagasaki

Developed under the Manhattan Project (US, UK, Canada) led by physicist J. Robert Oppenheimer.
"Little Boy" dropped on Hiroshima — 6 August 1945: 70,000–80,000 killed instantly; another 60,000 died later from radiation. The entire city was obliterated in seconds.
"Fat Man" dropped on Nagasaki — 9 August 1945: approximately 40,000 killed instantly; more died later.
Japan surrendered on 2 September 1945 — WWII ended.
The use of nuclear weapons ushered in the Nuclear Age and began a global debate about the ethics of weapons of mass destruction.

5. Consequences of the Second World War

Defeat of Axis Powers

Germany, Italy, and Japan were completely defeated. Their leaders were dead (Hitler — suicide, Mussolini — executed by partisans, Hirohito — Japan surrendered).
Nuremberg Trials (1945–46): Nazi leaders (Göring, Ribbentrop, etc.) were tried for war crimes and crimes against humanity. Many were hanged. Established the principle that individuals are responsible for war crimes even if following orders.
Germany was divided into East Germany (communist, under Soviet control) and West Germany (democratic, under Western Allies).
Japan was occupied by the USA; given a democratic constitution; permanently renounced war in Article 9.

Formation of the United Nations (1945)

The United Nations (UN) was established on 24 October 1945 to maintain world peace and prevent future wars — replacing the failed League of Nations.
Unlike the League, the UN included both superpowers (USA and USSR) and had a stronger Security Council with enforcement powers.

The Cold War

Concept Cold War (Meaning): A state of political, ideological, and military tension between the USA-led Western (capitalist) bloc and the USSR-led Eastern (communist) bloc after WWII. It was called "cold" because there was no direct armed conflict between the two superpowers — instead, they fought through proxy wars, arms races, propaganda, and economic competition. The Cold War lasted from approximately 1947 to 1991 (dissolution of the USSR).

Fact NATO — North Atlantic Treaty Organization:
A military alliance formed on 4 April 1949 by the USA, United Kingdom, France, Canada, and other Western democratic nations. Based on the principle of collective defence: if one member is attacked, all members will defend it (Article 5). Headquarters: Brussels, Belgium. NATO was the Western response to perceived Soviet expansion in Europe.

Warsaw Pact (Warsaw Treaty Organization):
A military alliance formed on 14 May 1955 by the USSR and its communist Eastern European satellite states (East Germany, Poland, Czechoslovakia, Hungary, Bulgaria, Romania, Albania) as a counter to NATO and to West Germany joining NATO. Headquarters: Moscow, USSR. It was dissolved in 1991 when the Soviet Union collapsed.

Other Major Consequences

Start of the Cold War — the USA and USSR emerged as two superpowers, dividing the world into two rival blocs.
Decolonization — WWII weakened the European colonial powers; nationalist movements in Asia and Africa gained independence (India — 1947).
State of Israel (1948) — established as a homeland for Jewish survivors of the Holocaust.
Marshall Plan (1948) — USA provided $13 billion to rebuild Western Europe.
Approximately 7–8 crore (70–80 million) people died — soldiers and civilians. The Holocaust killed 6 million Jews.