The main idea of the video is to support street artists and to be nice to them.

This flash-mob was filmed in Sabadell, a tourist city in Spain known for its historic sites where we generally find street artists. One of these artists was this correctly dressed cellist preparing his keys.

Everything started when a little girl comes and drops a single coin in the hat. The cellist started his performance, as he plays, other street musicians started to appear from nowhere and joined the cellist to make this stunning show!
I feel human again every time I watch this.