There are probably easier ways to set a world record, but Rudiger Koch has found his method 11 meters (36 feet) under the sea.
He's been living in a submerged capsule off the coast of Panama for two months – which means, he told a visiting Agence France-Presse (AFP) journalist, he has about two more to go.
"The last time I checked, I was still married," he joked as fish swam through bright blue Caribbean waters outside the portholes.
But Koch, a 59-year-old aerospace engineer from Germany, has grander plans than simply notching a record. He says his stunt could change how we think about human life – and where we can settle, even permanently.
"Moving out to the ocean is something we should do as a species," he told AFP.
"What we are trying to do here is prove that the seas are actually a viable environment for human expansion."
Koch's 30-square-meter (320-square-foot) capsule has most of the trappings of modern life: a bed, toilet, TV, computer and internet – even an exercise bike.
The only thing missing? A shower.
His home under the sea is attached through a vertical tube to another chamber perched above the waves, housing other members of his team – and providing a way for food and curious journalists to be sent down.
The underwater chamber, meanwhile, provides a shelter for fish and acts as an artificial reef – providing an environmental benefit.
"In the night, you can hear all the crustaceans," he said. "There's the fish out there, and there's all that stuff, and that wasn't here before we came."
On a small bedside table lies Jules Verne's "Twenty Thousand Leagues Under the Sea," a 19th-century sci-fi classic.
An admirer of the novel Captain Nemo, Koch, who went down on Sept. 26, hopes to come up for air on Jan. 24, surpassing by 20 days the record held by American Joseph Dituri, who spent 100 days submerged in a Florida lake.
Two clocks show how much time has passed – and how much remains.
A narrow spiral staircase leads to the chamber above, and the entire contraption is located some 15 minutes by boat from the Puerto Lindo coast off northern Panama.
Four cameras film his moves in the capsule – capturing his daily life, monitoring his mental health and providing proof that he's never come up to the surface.
Eial Berja, an Israeli, operates them from the section above while minding the electricity and backup generator.
It's not all easygoing, he told AFP, noting that a heavy storm almost ended the project.
Outside the media, Koch's only visitors are his doctor, children and wife.
Grant Romundt from Canada is supporting the project. He and Koch have grander visions linked to the libertarian – and at-times controversial "seasteading" movement that envisions ocean-based communities outside government control.
Though he still has a long way to go to resurface, Koch knows exactly what he'll do first once he's back on land: "a shower, a real shower."
