It's one of those flash mobs, the kind that you've probably seen a bunch of. I find this one particularly enjoyable -- not just for the mob, but the venue, the song and how well and fluidly it's done. It takes place at the old, elegant train station in Antwerp, a city of 500,000 in Belgium. At times, it seems like most of them are here, singing along.
But enough of that. Let's start at the very beginning, a very good place to start.