The fabled expedition of Ernest Shackletonthe Anglo-Irish explorer who led 27 men on a voyage to Antarctica in 1914 aboard the three-masted barquent schooner Enduranceonly to see his ship sink and to spend the next 500 days trying to survive and get back to civilization sounds like something you read about in history books – or maybe a fairy tale. It’s a tale so distant from our time, so rooted in a pre-technological world, that the idea that you could actually see it as it happens seems wonderful.

Still, Shackleton, who had an early 20th century showman’s flair for publicity, brought a filmmaker with him as part of the crew – photographer and cinematographer Frank Hurley, who filmed the entire voyage. So even when Shackleton and his men were stranded at the bottom of the earth, trapped in an endless expanse of pack ice, their daily routines, their research, the whole ordeal frozen in time, were photographed and recorded.

The Titanic’s voyage took place in 1912, two years before Shackleton’s expedition, and just imagine if the Titanic’s fate had been captured on film, the footage preserved under the sea and then recovered. It would feel like you were witnessing the uncanny. The footage of Shackleton and his men evokes a touch of that level of awe. It’s transporting, like a time machine. I first encountered this film – and indeed the whole saga – when I saw “The Endurance: Shackleton’s Legendary Antarctic Expedition”, the great 2001 documentary about it. That film, in its way, cast an aesthetic maritime spell.

“Endurance,” the new NatGeo documentary about Shackleton’s voyage, is very good, but its tone is less poetic, more scientific. The film crosses two journeys: Shackleton’s expedition (which it shows us in exquisite detail) and the attempt in 2022 by a team of researchers, led by the venerable maritime archaeologist Mensun Bound, to trace Shackleton’s journey and locate his sunken carcass. ship, 3,000 meters below the surface. (They eventually found it.)

The wreck of the Titanic was discovered in 1985. After that, locating the wreck of the Endurance had become the holy grail of underwater historical treasure hunts. Paralleling that mission with Shackleton’s own, “Endurance” creates a bit of a slim equation (as if the distance journeys were equivalent!). Yet the film becomes a meditation on the meaning of two ages: one rooted in 19th-century customs – in faith and wonder, in man turning against the elements – the other governed and protected by technology. One era feels religious, the other secular. I wish I could say that the crossover heightened the film’s tension (it doesn’t), but it’s gratifying to see the stories meet in the middle.

Directed by Elizabeth Chai Vasarhelyi, Jimmy Chin and Natalie Hewitt, “Endurance” is a rigorous documentary adventure film. It is based on the letters and diaries of Shackleton and his men; at one point Shackleton wrote to his wife saying that he could hardly describe the thrill of exploring places and things that no man had ever seen before. It was the main attraction of Shackleton’s expedition – his fourth attempt to reach Antarctica. And he never reached it. When he and his team sailed from South Georgia, the whalers there warned them to postpone the trip, saying the conditions would be too forbidding. But Shackleton, always desperate for funding, felt he could not turn back. After six months he and the crew were caught in the icy Weddell Sea and the ship soon went down.

The men we see in the old photos look strangely calm. They had provisions and lifeboats, which when stowed with gear weighed a ton each; the men had to drag those boats across the ice. Later, after they wash up on Elephant Island and are at the end of their tether, Shackleton takes five men in a whaleboat to sail the 800 treacherous nautical miles to South Georgia, a landmass they must then cross, scaling mountains and crossing icy abysses. You know it beyond the harsh extreme of it. (This is what faith looks like.)

The film uses enhancements such as coloring and sound effects, the sort of thing I was opposed to until I saw Peter Jackson’s revealing WWI documentary They Shall Not Grow Old. The centuries-old silent films in “Endurance” have been renewed with respect for its truth. I wish the movie hadn’t mixed in the re-enactments though. It is better to let us imagine what we cannot see. But what we see in “Endurance” is quietly astonishing.