If you live in a city and you've ever spent time on the internet, you're probably a little too familiar with street performers and flash mobs. But you've never seen anything quite like this. While performers line city streets all over the world and flash mobs are characteristically entertaining, something unbelievable happens when the two of them collide. Just ask the people who were in the right place at the right time when they walked through Spain's Plaça de Sant Roc back on May 19, 2012. When a little girl dropped some money into a cellist's hat, passersby were treated to a spectacle that left everyone singing. Although it was obviously a planned performance, there's something wonderful about the fact that it all started with one musician, a curious child, and a single coin. In many ways, music is the tie that binds. Its immense reach embraces people from all walks of life.