Zach passed away in May, 2013. This video is a tribute concert from December, 2013 where 5,000 people gathered at the Mall of America to sing his song. Beautiful.
More info on the day can be found by reading this article.
Recently, Anderson Cooper named Zach one of 2013's Extraordinary People. I'm sure you can find the segment online. It was really moving.
I figured this was a good video to wrap up 2013's Music Mondays.
And if you love the song as much as I do, go ahead and download it.