Glad you like it. I have it bookmarked in a small collection of flash mob videos that I watch from time to time. Most flash mob events are people dancing to music being played; however, I think the ones where people are actually doing the singing and playing of instruments themselves are usually much better.
As long as we are in "multi-national" mode in this thread - here are two more in my collection that clearly make a "humble brag" for those locations in my opinion: