Pentatonix is back with more music, and it's seriously giving us chills. In promotion of their upcoming EP, PTX VOL. IV - Classics, the a cappella group covered "Imagine" by John Lennon. Not only are their voices completely in sync, per usual, but the end of the video has an incredibly moving message. After passing around signs with cultural, ethnic, and religious labels they identify with, they turn them around to reveal the word "human." This may be one of their best covers yet.