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![Poles walk among the ruins of besieged Warsaw. [LCID: 47270]](https://encyclopedia.ushmm.org/images/thumb/2adc847c-f75f-4897-ad13-554b935e0949.jpg.pagespeed.ce.pb2uzIpAE_.jpg)
Featured Article
Invasion of Poland, Fall 1939
German troops invaded Poland on September 1, 1939, triggering World War II. In response to German aggression, Great Britain and France declared war on Nazi Germany.
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