This video was made in the Antwerp, Belgium Central Station (train). On a Monday morning, with no warning to the passengers passing through the station, a recording of Julie Andrews comes on the public address system singing “Do, Re, Mi.”
As the bemused passengers watched in amazement, some 200 dancers begin to appear from the crowd and station entrances.

Ah! How amazing if people could just burst into song and dance spontaneously without being branded 'crazy'. I think people will live longer and happier.

YouTube - Sound of Music | Central Station Antwerp (Belgium)