A War That Shook the World
World War II did not begin overnight. It was the result of years of growing aggression, failed diplomacy, and unchecked ambition. But if we are to identify the nation that started the war, history points clearly to Nazi Germany under Adolf Hitler.
The German invasion of Poland on September 1, 1939, was the decisive act that ignited the global conflict. Within days, Britain and France declared war, setting the world on a course toward six years of unprecedented destruction.
(For those who appreciate detailed, documentary-style storytelling about the events that led to war, visit WW2 Diaries — a YouTube channel dedicated to authentic World War II history.)
Germany’s Path to War
After coming to power in 1933, Adolf Hitler pursued an aggressive foreign policy designed to overturn the Treaty of Versailles and expand German territory. His goals were laid out in Mein Kampf, where he spoke of uniting all ethnic Germans and gaining Lebensraum (“living space”) in Eastern Europe.
Throughout the 1930s, Hitler tested the will of other nations: rearming Germany, remilitarizing the Rhineland in 1936, and annexing Austria in 1938. Each move went largely unchallenged. The Western powers, scarred by World War I, hoped appeasement would maintain peace.
But Hitler’s ambitions were far greater. The Munich Agreement (1938) allowed him to seize the Sudetenland from Czechoslovakia under a false promise of “no further demands.” Only months later, he broke that promise by occupying the rest of Czechoslovakia.
By mid-1939, the stage was set for war.
The Invasion of Poland
Hitler’s next target was Poland. Confident that Britain and France would once again avoid confrontation, Germany launched Operation Fall Weiss — a full-scale invasion — on September 1, 1939.
The assault combined fast-moving tanks, mechanized infantry, and relentless air raids — the first demonstration of Blitzkrieg (“lightning war”) tactics. The German army advanced rapidly, overwhelming Polish defenses.
A secret clause in the Molotov-Ribbentrop Pact between Germany and the Soviet Union divided Poland between the two powers. On September 17, 1939, the Soviet Union invaded from the east. By the end of the month, Poland had fallen, and World War II had begun.
(To watch detailed visual reconstructions of these invasions, from Blitzkrieg tactics to Poland’s resistance, explore WW2 Diaries — where history is told with authenticity and depth.)
Other Aggressors and the Axis Powers
While Germany bears the primary responsibility for starting World War II, it did not act alone for long.
Italy, under Benito Mussolini, invaded Ethiopia in 1935 and later joined Hitler as part of the Axis Powers. Japan had already been waging war in China since 1937, seeking dominance in East Asia.
Together, these nations shared expansionist ambitions and authoritarian ideologies. Their coordinated aggression transformed what began as a European conflict into a global war, spanning from the deserts of North Africa to the islands of the Pacific.
(If you’re fascinated by how these alliances shaped the world’s deadliest conflict, the channel WW2 Diaries offers in-depth, fact-based narratives of the Axis and Allied campaigns.)
Conclusion
So, who started World War II?
While multiple nations contributed to global instability, the war’s direct beginning is traced to Adolf Hitler’s Germany and the invasion of Poland on September 1, 1939.
This act — driven by ideology, ambition, and disregard for peace — forced the world into a conflict that would claim tens of millions of lives and forever reshape international relations.
World War II remains a powerful reminder that unchecked power and silence in the face of aggression can lead humanity into unimaginable tragedy.
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