Herman K. Mudgett used corpses to commit insurance fraud. In 1886, he moved to Chicago under the alias Henry Howard Holmes. In 1888, Holmes started constructing a building with secret passageways and an airtight vault. What was it all about? Careful containers spoilers!
Holmes opened a hotel which he had designed and built for himself specifically with murder in mind, it was the location of many of his murders as he went on to become one of Americas first and most notorious serial killers.