4. The Exorcism Of Emily Rose.
A legal drama movie released in 2005, it was based on the true events of Anneliese Michel, a girl who was said to be possessed by multiple evil spirits.
Badlands is a 1973 American crime film loosely based on the real-life murder spree of Charles Starkweather and his girlfriend who murdered 11 people.
6. Texas Chainsaw Massacre.
Also one of the most disturbing movies ever made, Texas Chainsaw Massacre was based on the killings by Ed Gein who killed and skinned his victims and wore their scalp on his face.