How do people react when they see a mysterious door in the middle of a train station? Do they pass by it, or are just too curious to do so? Blake Grigsby, a YouTube prankster, wanted to know the answer to these questions so he staged an amazing hoax. He placed a mysterious door in the middle of Chicago Union Station Great Hall with a strange cryptic sign that said ‘What Is behind the Door?’ next to it. The prank revealed not many people can resist the temptation of opening a secret door. Watch what happened after these people’s curiosity got the best of them.