The McKamey Manor, in San Diego, California, is the world’s most terrifying Halloween haunted house. A tour can last as long as 8 hours. Guests must undergo a health check before being allowed into McKamey. Heads are immediately shaved before guests are bound, slapped and forced to endure snakes, tarantulas and rats. Some people are held hostage while others are covered in fake blood. No one has ever lasted more than six hours in the home.