On December 26, 1973, The Exorcist, a horror film starring the actress Linda Blair as a girl possessed by an evil spirit, makes its debut in theaters; it will go on to earn a reputation as one of the scariest movies in history. The Exorcist was based on William Peter Blatty’s 1971 novel of the same name, about the last sanctioned Catholic exorcism to take place in the United States, in the late 1940s.

Source: History