What event brought on the beginning of world war ii in europe? germany's takeover of czechoslovakia, signing of the treaty of versailles, or hitler's invasion of poland

Hitler's Invasion of Poland on 1st September 1939, was the immediate cause of the second world war.

Explanation:

As Germans continued their aggression after the first world war, violation of the Versailles treaty continued but in this case, no one took great action against Germany.

On 1st September 1939, Hitler invaded Poland and with immediate effect, France and Britain declared war on Germany, which was on 3rd September, 1939.  Initially, Germany had desire to control the land and broke the Munich Pact, which was an agreement.  She took the rest of Czechoslovakia.

Upon Invasion of Poland and declaration of war on Germany by Britain and France, the World war  II started from this point.

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