Murder Hotel: The Story of America's First Serial Killer (2005)

A documentary about H.H. Holmes who was a famed serial killer in the late 1800s. He had a whole murder castle built specifically for that purpose. He spent nearly a decade hiring and firing builders to add pieces to his house that included pipes for pumping gas into bedrooms, a room built specifically to suffocate people, and a murder basement where he would strip the skin from his victims.