One hundred sixty years ago, 1851, the first World's Fair took place in London's Hyde Park. Forty-two years later, one man would use the Great Exhibition as a cover up for one of the most infamous, yet little known crimes of all time.
Meet H. H. Holmes, America's first (second? - google servant girl annihilator) serial killer. More prolific than Jack the Ripper, and just as brutal.
Except for the fact that he got caught. Yeah, don't do that.