H. H. Holmes was America’s first serial killer. He is believed to have killed from 20 to 200 people before his execution, thus becoming one of the most successful serial killers of all time. Holmes was based in Chicago and lured people to his castle during the World’s Columbian Exposition. The Exposition resulted in an enormous influx of "strangers" to Chicago who were isolated from communication with their families and friends.  The Exposition provided a distraction allowing Holmes to commit homicides without the police or the acquaintances of the many victims noticing his devious deeds (Depraved).