"Hallelujah" indeed. Last month, famous a cappella group Pentatonix released their version of the iconic song, and it's haunting and beautiful enough to give you instant goosebumps. The song is fresh off the group's new Christmas album, A Pentatonix Christmas, which dropped on Oct. 21. It's especially poignant given songwriter Leonard Cohen's recent passing. This isn't the first time we've heard them slay a Christmas classic; last year, they busted out with a music video for "Joy to the World". But let's just say this stunning release might be their best yet.