Nightmares Fear Factory has good reason to bill itself as one of the scariest and best haunted houses this Halloween season. The haunted house in Niagara Falls, Canada, is so scary that visitors are told to scream a code word - "Nightmares" - if they need to quickly leave. Around 130,000 people and counting have "chickened out" so far, but a brave few have made it through. Luckily for us, the brave's frightened and hilarious reactions are captured on camera. Click through to see the moment these people may have wished they'd screamed "Nightmares." And click HERE to read the legend of Nightmares Fear Factory.