This article from the Journal of Diving History is a tribute to Don Walsh, a renowned deep-sea explorer. It recounts his historic dive to the deepest part of the ocean, the Mariana Trench, in 1960. The article also highlights Walsh's contributions as an ocean scholar and educator, as well as his involvement in ocean science and policy. The author, Dr. Joe MacInnis, reflects on his personal relationship with Walsh and their shared passion for deep-sea exploration.