The Invasion of Poland in 1939 The invasion of Poland took place on September 1,1939. This invasion marked a change in history for the whole world. It started World War II. There were many reasons for the start of the war, and one it started the world would never be the same. Cities and people were destroyed. Unimaginable things took place in Poland during this time, things that will never be forgotten. The invasion lead to a great amount of bloodshed, but Hitler needed to be stopped and if he wasn't there would have been even more innocent people murdered. In the early 1900's Germany was part of the axis countries. Poland was in a decent state of affairs. The tw