‘Endurance’ Explorers and Filmmakers on Capturing the Shipwreck’s ‘Holy Grail’ Discovery, Recreating Ernest Shackleton’s Voice With AI and Restoring Century-Old Footage

When the crew aboard the S.A. Agulhas II set out in early 2022 to search for the Endurance shipwreck, it seemed nearly impossible.

“It’s the holy grail,” Nico Vincent, the sub-sea manager on the expedition, tells Variety. “It’s the most complicated one. Just being able to reach the field and dive three kilometers beneath the ice, it’s the level of complexity of walking on the moon.”

The Endurance, commanded by explorer Sir Ernest Shackleton on an expedition to traverse Antarctica from one coast to another, sank in the Weddell Sea in November 1915 as its 27-member crew looked on. Over the next 308 days, the men faced starvation and frostbite as Shackleton recruited five crew members to make the treacherous journey in a lifeboat to seek help on the South Atlantic island of South Georgia. Miraculously, when Shackleton returned to save the remaining men, he found all of them still alive. Hailed as one of the greatest survival stories ever, it’s become the stuff of legends — and its ship an elusive treasure underneath the sea.

“I can remember my old boss saying to me … I give you a 10% chance that you’ll get on to the sinking site,” says expedition leader John Shears. “So I said, ‘Well, Shackleton would have taken the 10% chance and so are we.'”

Shears had also led a failed expedition to find the Endurance in 2019, so the stakes were high. Despite the risk, he signed on again without hesitation. “There was unfinished business there,” he says. “For a polar expedition leader like me, it is the ultimate challenge.”

Thankfully, a documentary crew — led by filmmaker Natalie Hewit — was also on board the S.A. Agulhas II to capture the thrilling moment Shears, Vincent, marine archeologist Mensun Bound and historian-broadcaster Dan Snow unearthed the Endurance, perfectly preserved, over 3,000 meters under the sea. Once the groundbreaking discovery was made, National Geographic and Oscar-winning directorial duo Jimmy Chin and Chai Vasarhelyi joined the project with the idea of interweaving the March 2022 revelation with the original Shackleton story, told through archival footage and preserved diaries. The end result is the gripping documentary “Endurance,” premiering on National Geographic Friday night and available to stream on Saturday via Hulu and Disney+.

“When we heard that they had found the Endurance, we were immediately struck by the magnitude of the find but also the opportunity to use it as a kind of modern, relevant way to revisit Shackleton’s story,” Chin says. “We knew that we could kind of marry the two expeditions and be able to tell a parallel story.”

Somewhat surprisingly, the 1914 Shackleton expedition had a photographer and cinematographer on board in Frank Hurley. The footage he had captured — and somehow brought back despite the crew’s near-death experience — was being safeguarded by the British Film Institute, which agreed to restore and color treat it for the documentary despite strict rules in place.

“You have to assume the rest of the team, even in that era, was aware of how important it was to document and to preserve this and bring it back,” Chin says. “The amount of effort and time and thoughtfulness they had to move all the stuff into these little boats in the most treacherous seas in the world, not knowing if they’re going to live? I mean, the awe and respect I have for them…”

But the true way to bring the Shackleton expedition to life was through the diaries of the men on board. Chin and Vasarhelyi toyed with different ideas on how to translate the crew member’s words on screen, but after watching Morgan Neville’s Anthony Bourdain documentary “Roadrunner” — which controversially used artificial intelligence to reproduce his voice — they decided to recreate the voices of Shackleton and others using an AI tool called Respeecher.

“The way we used it is just as a craft tool,” Vasarhelyi explains. “It was an ethical way to use it, but it was also very opportunistic. It was more like, wow, we can tell a story and make use of an archive that exists and is legit, but not experienced this way.”

Watching the Respeecher tool in action for the first time paired with the color-treated footage, Vasarhelyi says she got “goosebumps throughout my entire body.”

“I’m watching this event that happened 110 years ago in the most remote place on earth, and that’s real,” she says, her eyes widening.

While the filmmakers were using new technology to enhance Hurley’s century-old footage, it was also integral to finding the Endurance itself. Sub-sea engineer Vincent was brought on after the failed 2019 expedition to create a deep-sea AUV (autonomous underwater vehicle) attached to an eight-kilometer fiber-optic cable that allowed the vehicle to survey deeper waters — and not get lost in the process, as the 2019 AUV had. A laser scanner was also developed to make a detailed 3D digital model of the shipwreck.

In “Endurance,” viewers see the team of explorers find the shipwreck in real time with just days left in the expedition — a moment that no one on board will ever forget.

“It was just this massive sunburst of pure joy when it happened, and it went right through the ship,” Bound says. “There was this kind of shouting coming up from the mess room sort of building to an orchestral crescendo.”

Shears and Bound were actually off the ship, taking a walk on thick ice nearby and figuring out how to break the news to the rest of the crew that it was time to give up. Vincent took this opportunity to play a bit of a prank.

The duo were called to the bridge of the ship by its captain, and Shears “automatically thought this is desperately bad news — we’ve lost the AUV, or even worse one of Nico’s team has had a bad accident on the back deck.” Vincent and the film crew kept their faces glum as the two approached, and then he simply handed Shears his iPhone with the sonar picture of the Endurance pulled up.

“The emotion you see in the film, that is exactly as it happened,” Shears says. “It’s a mixture of relief, happiness, amazement, joy all rolled into one. It was the most incredible moment because I thought it was going to be the exact opposite. So first thing I do is go and hug him, and then a bit later I punch him.”

Adds Vincent with a chuckle, “As you can see, I like to joke.” 

For producer Ruth Johnston, the theme that connects the 2022 expedition with that of Shackleton is “that you have to fail to succeed.”

“I think that 2019 failure, without all the people who worked on that expedition, this one might not have been successful,” she says. “It’s clear as well in the 1914 Shackleton expedition.”

The Endurance is now protected under the Antarctic Treaty as a historic subsea monument, and will stay on its seabed home instead of being raised to the earth. But, as Shears and Vincent point out, there’s no need with the 3D digital model that was produced — and the awe-inspiring 4K footage that can be seen at the end of the film.

“You can look at that vessel in your school classroom, in your bedroom, in your living room with your mum and dad and just marvel at it,” Shears says. “It is quite incredible that this ship, when she sank on the 8th of November, 1915, she goes 10,000 feet on to the sea floor and how you see her now is exactly how Frank Hurley photographed her then.”

Though the Endurance may have been found, for Shears and Vincent, the work is not yet over. After Shears attempts in 2026 to cross South Georgia as Shackleton did during his expedition, the two want to do more dives to fill out the 3D model and perhaps discover more artifacts on the ship with a mini ROV (remotely operated underwater vehicle) that Vincent hopes to develop.

As for Chin and Vasarhelyi, they are continuing to work on film projects including an adaptation of Michael Crichton and James Patterson’s “Eruption” and another survival documentary about a plane crash in the Colombian Amazon. And, a few weeks ago, Chin and a team of climbers and filmmakers stumbled upon a groundbreaking discovery of their own on Mount Everest: what appears to be the boot of British explorer Sandy Irvine, who disappeared during a 1924 trek up the mountain. The remains of his climbing partner, George Mallory, were found in 1999 by an expedition led by Chin’s close friend and mentor Conrad Anker, but no trace of Irvine had been found — until now. Chin and National Geographic broke the news with a photo of Chin posing with the boot (to any backlash, he says: “We were just kind of documenting the moment, you know?”).

“The fact that our path crossed this boot, which I’m fairly convinced at the very most had melted out maybe five days before we found it — that intersection of time and space is wild,” Chin says. “I mean, it feels eerie in a way, how everything lined up. It was a really incredible moment and you know, I think that our greatest satisfaction in it is that it hopefully brings some closure for Sandy Irvine’s relatives and family.”

So, is a documentary about that discovery the next on Chin and Vasarhelyi’s docket? “I can’t say anything definitively,” Chin says, “but we are certainly considering exploring that story a bit more.”