Stalin's regime.
In 1930s thousands of people suffered in USSR from Stalin's dictation. He had some kind of paranoia. During this period people could get capital punishment and being sent to the coldest parts of the county for nothing. This period was one of the hardest periods in history of the world's biggest country. One of the reasons why Soviet Army was defeated during the first two years in World War II was that Stalin had killed many talented generals.
My both parents suffered from Stalin's regime. They were sent to Kazakhstan and their homes and property were confiscated.