It's been almost 21 years since Princess Diana's tragic death, and we're honoring her memory by looking back at her sweetest mom moments. Even though she passed away in August 1997, her spirit lives on through her two sons. While Prince William is keeping royal parenting traditions alive with his own family, Prince Harry has carried on his mother's legacy through his various philanthropies. Over the years, the royal has gotten more comfortable talking about his late mother, and in turn, has given us a glimpse at their unbreakable bond. See some of their sweetest pictures together below.