The sounds of the Sistine Chapel Choir

The singers are at the pope's side for all important papal celebrations. The Sistine Chapel Choir performs when the pope presides over the Christmas Eve mass in St. Peter's Basilica, and they sang at the private Vatican mass to honor Pope Francis's 80th birthday.

And as the oldest choir in the world — evidence of their existence dates back to the seventh century — they've seen a few popes.

The bulk of the choir's repertoire is sacred music composed by Giovanni Pierluigi da Palestrina. Palestrina, who lived from 1525-1594, composed his music with the Sistine Chapel in mind, drawing inspiration from Michelangelo's colorful frescos adorning the walls and ceiling.

With masterpieces like The Creation of Adam in the center of the ceiling above them and the grandiose The Last Judgment positioned behind them on the altar, even the choir felt transported in a recent concert.

"When we sing Palestrina, it's not like looking at a fresco," says Mark Spyropoulos, a baritone from Britain and member of the choir. "It's the equivalent of being in a fresco."   

This video was originally published in 2016.