In the early 1930s, the leader of the Soviet Union Joseph Stalin, decided to force Ukrainian peasants to give up their farm land and join collective farms as good Soviets would do. He did this by taking away their food and starving millions to death.
At the time, Ukraine was the breadbasket of the USSR, producing enough wheat to feed the entire country. But, millions still died of hunger.
Here is a video of a man who illegally documented the horror, by secretly taking pictures which he smuggled out of the Soviet Union.
Stalin, and the Soviets, of course denied everything. It was only decades later that the truth become known.