Beloved French explorer Jacques Cousteau spoke for the seas. The inventor, conservationist and filmmaker rose to fame in the ’60s thanks to the adored series “The Undersea World of Jacques Cousteau,” which brought the wonders of Earth’s waters into the living rooms of children and adults across the globe. One part weathered sea captain, two parts mad explorer, with a dash of Mr. Rogers, Cousteau (and his iconic red beanie) became synonymous with adventure, freedom and conservation.

But despite a few Wes Anderson homages and references on film, this highly influential figure has faded from most memories. His footage of turtles and shirtless frenchmen aboard his mighty Calypso has been forgotten from popular culture. Even more upsetting is the erasure of his exceedingly early warnings about damaging the world’s most precious resource: our oceans.

Known for her past documentaries on other historical figures such as Bobby Fischer, Marilyn Monroe and Nina Simone, director Liz Garbus pointed to that lack of awareness as the impetus for “Becoming Cousteau.”

“Cousteau was a childhood hero of mine,” Garbus explained on Variety‘s “Doc Dreams,” presented by National Geographic. “I grew up loving his show and dreaming of riding aboard the Calypso as a child. As a grown-up, in reading a book to my son about Cousteau, I realized that his whole story was being lost to a new generation. I tried to go online to show my son some of the films that I had enjoyed so much as a child, I couldn’t find them. I looked for a doc about Cousteau, couldn’t find that. So I began to dig in a little and when I did, I realized that it was more than just kind of wanting to share those adventures with my kids, but also it was about the message that became his legacy. The message of environmental protection and speaking on behalf of the oceans. It felt like a film that was really a voice that was really relevant today.”

With the help of The Cousteau Society, Garbus and her producer combed through 500 hours of vintage footage, discovering a man who documented his entire life, from his early days spearfishing in the South of France to his last days championing the fight against climate change with world leaders. It was a veritable treasure trove of unknown Cousteau oddities and shocking revelations. Garbus uncovered details about how he helped innovate and create scuba equipment, harrowing footage of the loss of his first mate when testing deep sea diving equipment, even video detailing his time with the French Navy post-World War II, retrieving fallen soldiers from downed planes and sea battles.

So much footage, in fact, that Garbus calls his vault of film the first reality show. So what compelled this man to keep a camera rolling at all times? “He says, ‘I’m addicted to filmmaking, it’s a sickness. I feel miserable and I’m not making a film,'” said Garbus. “So from an early age he was playing with cameras, taking them apart, putting them back together. It was an obsession. I think people think of Cousteau as this man in a red cap, the captain of a ship, but really he was an innovator and inventor. And by his own estimation, most of all, filmmaker.”

That being said, his life on the seas wasn’t always driven by a desire to observe and preserve. A big reveal in “Becoming Cousteau” was how exploratory oil drilling supported much of the captain’s early days. Plus Cousteau and his crew weren’t always kind to the delicate ecosystems they encountered and filmed themselves using dynamite to uncover fish populations, forever damaging many reefs. To Garbus, it was imperative to show this transition — his change from careless young adventurer to conservationist — and his fervor to address his own misdeeds became the anchor of her documentary.

“I started to listen to Cousteau’s interviews later in life, where he talked about some regrets he had, regrets about the way he and his crew interacted with animals and fish. The way that he had accepted money from oil companies. He had regrets and he talked about the film ‘The Silent World’ and not being able to even watch it anymore because of the treatment of sharks and that film. So when I heard those stories, that for me then became the focal point of the film. There’s this transformation of a kind of adventurer, explorer hubristic, do anything it takes to go deeper, to go further, to somebody who was really becoming a steward and a protector.”

Garbus was not interested in showing a one-sided view of Cousteau; she knows audiences are far too smart for that and that’s not real life. “We’re all flawed,” she said. “But if you can be flawed and overcome some of those flaws, or if you can find ways to actually have an impact despite mistakes, that’s a really important message for where we are today, especially around climate change. I think that showing somebody, warts and all, is actually more inspiring than not.”