A MUST SEE A Cappella Group Covering Taylor Swift’s “I Knew You Were Trouble”

We often are amazed with performances from our musical artists that can sing and play an instrument.  But, to watch a group perform a song with their voices ONLY?  This is truly amazing!  That's right, no instruments in this video at all.  The group is, Walk Off the Earth.  The song is, Taylor Swift's "I Knew You Were Trouble".   Fantastic!