Some of the most infamous criminals in history experienced murders first-hand before they starting doing the killing themselves.

The United States may have churned out the highest number of serial killers in the world over the years, but it certainly doesn't hold exclusive rights on brutal murders. Learn about some international serial killers and how their respective countries handled their crimes.

Although cannibals have always existed throughout human history as a cure for overpopulation, a means of survival during a famine, or even a way to contend with grief, what's more rare are murderers who kill for sport and then devour their victims. We talk to Dr. Eric Hickey, a forensic psychologist, on why some killers eat their prey.