The Germans started sealing off Krakow to establish a Jewish concentrated ghetto there.
More on the evil of Germany in Poland can be read about here:
Today in World War II History—March 3, 1941
Mars Candy received the patent for M&Ms on this day in 1941. They were based on a British candy called Smarties which Frank C. Mars, the owner of the company, had observed soldiers eating during the Spanish Civil War. The first customer was the U.S. government which purchased them for servicemen serving overseas as they wouldn't melt.
On the same day, Winston Churchill urged FDR to ignore the growing caloric crisis in France.
Churchill – ‘Don’t feed the French’
Turkey had second thoughts about its non aggression pack with Bulgaria and cancelled it after only one week of existence. The U.S. froze Bulgarian assets in the country.
Guardsmen from Pine City, Minnesota, departed for Federalized service.
Other events in World War Two from this day: