Fifteen years ago, the producers of The Oprah Show staged a massive flash mob in Chicago for a stunned Oprah Winfrey, in celebration of her 24th season. Tens of thousands of people gathered to perform it.

The expressions of confusion, realization, and joy that parade across Oprah’s face as it slowly dawns on her what’s happening are absolutely priceless.

I get emotional watching a group of people come together to perform a synchronized dance, especially when it starts small and just… grows. From Soul Train, to party line dances like the Electric Slide or Cupid Shuffle, to music videos like Thriller, synchronized, choreographed dance numbers are a physical manifestation of humanity’s need for communal togetherness.

In musical theater, when your emotions are too strong to speak, you sing; when they’re too strong to sing, you dance. A flash mob breathes life into this, imbuing emotion into a few fleeting minutes that took hours or days to prepare for. A flash mob created to elicit joy from one person may be the ultimate expression of love, and this crowd loved Oprah.

I also recommend you watch the behind-the-scenes and making-of videos. It seems Oprah isn’t a big fan of surprises, so this was a bit of a calculated risk by her team. Watching Oprah bop around in excitement, I’d say it worked out OK.