The Fear Factory in Salt Lake City, Utah, is not your average haunted attraction. The address begins with 666, which should have been a suitable warning for the cement factory that originally occupied the space in the 1800's. Cursed by horrific deaths due to dangerous factory equipment, the cement company eventually closed its doors, leaving its six buildings and two underground tunnels to become a city for the homeless until it was transformed into the world-famous Fear Factory in 2011. Plagued by paranormal activity, there's a reason you have to sign a waiver to get in. Enter at your own risk...