Stalin is widely regarded as one of the worst dictators in human history, creating the communist Soviet Union and stripping citizens of their rights. There are many instances of his human rights violations, too many to describe here in their entirety, but there are several key points.
Stalin's enforced occupation of Eastern Europe is one of the first examples of his human rights violations. After WWII was over, military occupation in Eastern Europe was supposed to be regulated by agreements set in place just after the war. During this occupation, he restricted religion and free speech, two central human rights.
One of the greatest examples of his human rights violations was an artificially imposed famine in his own country. He created scarcity by exporting nearly all of the crops produced in the country to bolster the national profit while punishing and restricting the people of the Soviet Union to further his control over them.