HH Holmes and the Murder Castle

HH Holmes is the most notorious serial killer in the history of...serial killing. Most people think of Jeffrey Dahmer when they think of serial killers, but he killed 17 victims where as Holmes confessed to killing 27, and some people think he killed as many as 200. If you you judge a serial killer by the numbers, Holme's has Dahmer beat hands-down.
Any way, he built a three-story building that some call the "Murder Castle" because it supposedly had trap doors, gas chambers, and torture chambers (as reported in Eric Larson's "Devil in the White City"), but is that true or exaggerated Chicago bulls*t like Catherine O'Leary and Steve Bartman.
I've talked enough. You're going to have to watch the video to find out the rest of the story.