The story so far:
Hitler's troops marched into Poland with orders to kill anyone who resisted German rule. They tried to wipe out Polish culture as much as possible. They even changed the names of towns and cities in Poland, and replaced Polish names with German names. For example, the city of Gdansk was re-named Danzig. Hitler told the German army commanders to round up any Jews that they found in Poland and kill them too. Huge concentration camps were built in Poland especially for this purpose.
If any Jews were found, they were reported to the Germans immediately. Anyone was allowed to report a Jew to the authorities. If you thought that your next-door-neighbor was a Jew, you could go to the nearest police station and tell them about it. The police would go the house, and knock on the door. If nobody answered, they would kick down the door, and arrest everyone inside. They would take all the adults out of the house, the children would be taken too. The whole family would be taken to the nearest railroad station and they'd be put on a train.
The train would take them to the nearest concentation camp. In the camp, the Jews would be sorted out. If a Jew was young enough to work, he was forced to work in a slave-labor camp. Often, these Jews were forced to make bombs and weapons for the German army. If a Jew was too old to work, they just killed him. They figured there was no point in keeping him alive. If a Jew was too young to work (like children and babies) they would kill them immediately.
The Germans invaded France, and while they occupied France, they killed any Jews they found in France. After the Germans invaded Russia, they killed any Jews they found in Russia. Hitler hated the Russians nearly as much as he hated the Jews. One of the most cruel actions in world war two was the seige of Leningrad. The city of Leningrad was in the far north of Russia. The Germans sent troops to surround the city of Leningrad, and they would not allow any trucks to reach the city. If they found a truck full of food going to the city of Leningrad, they would stop the truck, kill the driver, and steal all the food from the truck. As a result, no food was reaching the city of Leningrad. Over a million people in Leningrad starved to death while the Germans held the city in their grip.
The people in Leningrad refused to surrender. The Germans kept Leningrad surrounded for months. Finally, the Russian army went into the north, to attack the Germans and liberate the city of Leningrad. When they got there, they found over half the city's population was dead! Men, women, and children lay dead, victims of the German army! The Russian army brought in supplies of food as fast as they could, but it was too late! Over half the city's population had been starved to death by the German army!