More than 4,000 people will gather in the Mall of America rotunda tomorrow to honor Zach Sobiech, the 18-year-old from Lakeland who died from osteosarcoma earlier this year.

Many of us know Sobiech from his popular single “Clouds,” which debuted Dec. 5, 2012. The song hit No. 1 on iTunes, while its music video garnered more than 8.3 million views. Eleven million-plus have watched the documentary that captured his last days, and tomorrow, on the anniversary of the song’s release, an all-ages choir will sing a rendition of “Clouds,” honoring Sobiech and his family.

The event is part of the 15th annual KS95 for Kids Radiothon, benefitting Children’s Cancer Research Fund and Gillette Children’s Specialty Healthcare. All are invited to come watch.