THE DEEPEST BREATH, which debuts on Netflix on July 19, tells the gripping, tragic story of two free divers, the world-record-holder Alessia Zecchini from Italy and her vigilant coach and safety expert, Stephen Keenan from Ireland. I won’t give away the nature of the tragedy, which took place in Dahab, Egypt, because McGann unspools it so suspensefully and movingly. But I will say that the documentary braids together many kinds of love: love between people, love of the ocean, love of excellence and adventure, love of original lives, love of tight-knit communities, and love of travel to places that are breathtaking, in both senses of the word.