History quiz

What event triggered the start of world war ii?

The invasion of Poland by Germany on September 1, 1939, is widely considered the event that triggered the start of World War II.

Following the invasion of Poland, Britain and France, who had previously issued guarantees to support Poland's independence, declared war on Germany. This set off a chain reaction as allies on both sides of the conflict were drawn into the war. By the end of September 1939, the war had expanded to include other European countries, and eventually became a global conflict involving multiple continents.