The piece is "Lightning", by Phillip Glass. For those who can't see the video: Nine black-robed figures with tall pointy hats, out of the tops of which a great huge flame emerges, glide about; it's clear from their graceful glide and back-and-forth swaying that under the long robes are Segways. Eight of the nine carry various instruments: some percussion, some brass, I think a woodwind, and a banjo. The ninth member carries no musical instrument and has no hat, but instead holds two long flaming wands.
They glide around the circle in the middle of the crowd in an intricate dance, made more entertaining when the ninth member lowers the wands sprays fire from them to the ground.
The effect is that of a ritual from an unfamiliar culture: mesmerizing, clearly meaningful, sacred, and you are a guest who has been kindly allowed to observe.
This is why fighting the good fight, in whatever battle, is a worthwhile occupation: to create the space for beauty and wonder to exist in the world, to work a half-step at a time to build a place where not only are people not dying and starving and ill and miserable, but where everyone can be free to have a moment of joy and wonder, and express what moves them.