Getting Rid of Trotsky
Leon Trotsky played an integral role in the formation of the Soviet Union. As Lenin's No. 2, he founded the Red Army. But then Lenin died, Stalin took over and poor old Trotsky didn't take too kindly to his new ruler's ideals. After clashing with Stalin one too many times, he was thrown out of the Communist Party and exiled from the Soviet Union. Trotsky bounced around Europe for a while and then finally settled in Mexico, where he continued to campaign against Stalin.
In 1940, a very displeased Uncle Joe sent assassins to kill the revolutionary. A plan to open fire on Trotsky's house failed to kill him. They tried again in August of that year when Spanish-born KGB agent Ramón Mercader attacked the aging dissident in his study and buried a pickax in his skull. Trotsky suffered for the better part of two days before dying. The Soviets (obviously) denied any involvement in the assassination, and Mercader was sentenced to 20 years in a Mexican prison.