On the eve of Passover, Polish Jews rise up against Nazi Germany in the Warsaw Ghetto Uprising.
The Germans had sent troops into the Warsaw ghettos to begin the final round up of the Jews there, to be transported to various concentration camps for their eventual execution. The insurgents used Molotov cocktails and hand grenades, which were thrown at the troops and their tanks. They set fires wherever they could and generally created havoc over the next month. 17 Nazis were killed, but over 13,000 Jews were killed and 50,000 sent to the concentration camps anyway.
In mere words, it sounds as if the Jewish effort was futile and a waste of time. It was not. It was the strongest action of resistance to date by the people who were being executed en masse by the Third Reich. They fought and showed that the days where they would willingly accept their own destruction were over.
In 2012, April 19 is Holocaust Remembrance Day.