WATCH: You’ll never guess what’s behind this mystery door

When a mysterious door frame appeared in the middle of Chicago Union Station's Great Hall, onlookers began eyeing each other to see who would be brave enough to open it. A sign nearby asked: 'What is behind the door?' Eventually a few brave passers-by took a chance and turned the handle. Watch what happens when some unsuspecting kids, including a thrilled little girl and some fun-loving adults get a silly surprise... https://www.youtube.com/watch?v=XvOsh15hLIs