Okay, so back in olden times, people would grow crops like corn and wheat to make food. And when it was time to harvest all those crops, they would have a big celebration to say thank you to the gods for giving them a good harvest.
In Germany, a man named Adolf Hitler was in charge and he wanted to have a big harvest festival too. But he didn't want to thank the gods, he wanted to thank himself and his government for making sure there was plenty of food for everyone.
So they had this big festival called the Reich Harvest Thanksgiving Festival where Hitler and other important people would give speeches about how great they were for making sure everyone had enough to eat. They would also have parades and displays of all the food that had been grown that year.
But even though they were celebrating how much food they had, there were still people who didn't have enough to eat because of the war and other issues. So the festival was kind of like pretending everything was okay when it really wasn't.