Hollywood director James Cameron has returned to the surface after plunging nearly 11km (seven miles) down to the deepest place in the ocean, the Mariana Trench in the western Pacific.
He made the solo descent in a submarine called “Deepsea Challenger”, taking over two hours to reach the bottom.
He spent more than three hours exploring the ocean floor, before a speedy ascent back to the surface.
His craft was kitted out with cameras and lights so he could film the deep.
This is only the second manned expedition to the ocean’s deepest depths – the first took place in 1960.
The earlier descent was made by US Navy Lt Don Walsh and Swiss oceanographer Jacques Piccard.
They spent about 20 minutes on the ocean floor but their landing kicked up silt, meaning their view was obscured.
Before the dive, the Titanic director told the BBC, that making the descent was “the fulfilment of a dream”.
He said: “I grew up on a steady diet of science fiction at a time when people were living a science fiction reality.
“People were going to the Moon, and Cousteau was exploring the ocean. And that’s what I grew up with, what I valued from my childhood.”
Cameron’s last words before his descent were: “Release, release, release.”
The Deepsea Challenger was made in Australia.
Cameron spent the last few years working in secret with his team of engineers to design and build the craft, which weighs 11 tonnes and is more than 7m (23ft) long.
He describes it as a “vertical torpedo” that slices through the water allowing him a speedy descent.
The tiny compartment that the filmmaker sits in is made from thick steel, which is able to resist the 1,000 atmosphere of pressure he will experience at full ocean depth.
The rest of the vertical column is made from syntactic foam, giving it enough buoyancy to float back up.
It also has robotic arms, allowing him to collect samples of rocks and soils, and a team of researchers are working alongside the director to identify any new species. He says that science is key to his mission.
If successful, Mr Cameron’s multi-million-dollar expedition, which has been financed by the filmmaker himself, Rolex and National Geographic, is the first manned effort to the deep for half a Century.
In 1960, Don Walsh, a former US navy lieutenant, and Swiss oceanographer Jacques Piccard made the first historic dive in a bathyscaphe called the Trieste.
Don Walsh, who is now in his 80s, joined Mr Cameron and his team of engineers out at sea for the dive.
He said that getting to the deepest ocean was not so much a feat of engineering more one of imagination.
Before the dive, he told the BBC: “He (James Cameron) is a storyteller, and going back after 50 years is a great story.
“I thought it was a made-in-heaven match: his interest as a storyteller, his competence as an engineer, he has access to resources, sponsors and such, and made this all come together.
“It probably couldn’t have been easily done by any combination. It’s like the stars were in alignment, it all worked out.”
While manned exploration had until now seen a 52-year hiatus, scientists have used two robotic unmanned vehicles to explore the Mariana Trenches: Japan’s Kaiko made a dive there in 1995 and the US-based Woods Hole Oceanographic Institution’s vessel Nereus explored the deep in 2008.
Other teams, such as Scotland’s Oceanlab, have also been dropping simple landers loaded with bait and cameras into the deepest ocean.
While places like the Mariana Trench were once thought to be of little interest, there has been a recent resurgence of scientific interest in the deep.
Scientists are finding life that can resist the colossal pressures, from deep sea fish to shrimp-like scavengers called amphipods, some of which can reach 30cm long (1ft).