Two notorious tyrants in modern history were Adolph Hitler of Germany, who perpetrated the Holocaust and launched the deadliest war, and Josef Stalin of the Soviet Union, who unjustly imprisoned millions in harsh conditions. Others include Chilean dictator Augusto Pinochet, Pol Pot of Cambodia and North Korea's Kim Jong Il.
From 1922 to 1953, Stalin advanced Russia and the Soviet Union from an impoverished agrarian economy to a world industrial powerhouse. Along the way, he did murderous purges of his rivals and established the gulag system in which up to 40 million people were imprisoned in harsh conditions that resulted in the deaths of many.
Hitler took power in the 1930s and quickly quelled opposition, established the terrorist Gestapo police and concentration camps, and then began persecuting and finally mass-murdering Jews, Gypsies (also known as Roma) and other groups. He started World War II in a mad quest to rule the world.
Pinochet, who ruled Chile from 1973 to 1990, tortured more than 30,000 people and killed 2,279, the Valech report states. He also did summary trials, secret detentions and suppressed his political opponents.
Pol Pot ruled Cambodia from 1975 to 1979 and killed up to 25 percent of the country's population, which was 3 million people. He forced city dwellers to work on farms and abolished religion and education. Schools became prisons and torture places.
Kim Jong Il's regime, in power since 1991, reportedly keeps thousands of people in "re-education" and prison camps and does widespread torture, forced labor, trafficking of women and public executions for political reasons. His direly impoverished and malnourished people are largely cut off from the world and misunderstood.