A piano sat in Chicago's Union Station. A magical piano. It added a soundtrack to people's lives, joined in for some duets with a trumpet and harmonica player, and even played "Deck the Halls" when Santa walked by. But how is this possible? There was no one there to play it. Was it really magic or just some trickery? We skyped with Rob Bliss, the man behind this and other viral videos, like the homeless veteran transformation, to find out just how he did it and how musician Andrew Blendermann was able to hit the keys.