For very personal reasons, Harold Mendenhall has donated 100 gallons of blood...so far.

Prepare to be inspired!

84 year-old Harold Mendenhall began to donate blood in 1977 as a way to "honor his wife's struggle" with breast cancer. He has since lost his wife and two of his five children, but through his sorrow he is still grateful and plans to keep donating.

Get to know this wonderful man in the video below.