On Dec. 6, 2012, radio station KS95 in Minneapolis debuted “Clouds,” a song written by teenage cancer patient Zach Sobiech in response to being told he had less than a year to live.

The song became an Internet sensation, garnering millions of view on YouTube and quickly became the #1 song on iTunes.

Zach died on May 20. On Dec. 5, the anniversary of the song’s debut, 5,000 of his fans gathered at the Mall of America to remember him and sing his song in a touching tribute.

Related on MNN: Remembering Zach Sobiech