H.H. Holmes, also known as Henry Howard Holmes, was born Hermann Webster Mudgett in 1861. He changed his name after graduating from high school and embarking on a medical career that provided him with the skills needed to conduct his twisted experiments and gruesome acts.

What H.H. Holmes did to his victims lives on in infamy, as he is credited with being one of the first serial slayers in America. Holmes built his murder castle - named for its specific purpose of providing him with a place to slay his targets - in Chicago, and opened its doors to tourists visiting the nearby World's Fair in 1893. Some, if not all, of those tourists never made it home from the White City. What did the Devil in the White City do to them?

Holmes was detained by police in 1894 for insurance fraud, although the charges against him quickly expanded to include mass slaying. He received a capital sentence, and was hanged in May 1896. It's believed that he took hundreds of lives, although he only confessed to ending 27. These H.H. Holmes facts are just the tip of the proverbial iceberg.