Last summer, after six months of construction on a barge off the craggy Southern coast of Norway, developers and engineers filled the restaurant Under with 450 tons of water and were thrilled to watch it sink. When the structure’s 1600 tons of concrete had been manipulated into place by a floating crane and bolted to the ocean floor, and after the seawater had been pumped out and the unit sealed so none could rush back in, the owners had officially reached their goal. “It’s Europe’s first underwater restaurant,” says Stig Ubostad, who with his older brother and business partner Gaute Ubostad spent just over 8 million dollars to achieve their subaquatic dream.

Under was not conceived by a well-known chef or restaurateur looking to add a remote and romantic new dining room as an exclamation point on an established culinary empire. The Ubostad brothers are fourth-generation hoteliers whose great-grandmother started the family business by opening a campground in the Norwegian municipality of Lyngdal in 1934. Gaute and Stig, 45 and 43, respectively, now run two comfortable, conference-hosting hotels in the area and were thinking about ways to boost tourism around Norway’s sparsely populated southernmost tip.

“We wanted to build an attraction that would make us stand out,” Stig explains. “We wanted something that focused on the wild nature we’ve always loved, and lived with and that would also be about sustaining it.”

Under will officially begin serving an 18-course meal in its 40-seat dining room for the first time on April 2. “We’re sold out for the first six months,” Ubostad says. There will be a single seating per night. Dinner costs $270 per guest without wine.

The idea for the restaurant was first proposed to the Ubostads about ten years ago, by a friend who has since passed away. “It sounded crazy,” says Ubostad, “but people around here think of what’s possible rather than what’s impossible and, so, we just decided to do it.”

In 2015, the Ubostads started talking to engineers and architects and chose a small architecture firm—Rever & Drage, who kept an office in nearby Flekkefjord—to work on Under. The brothers were advised to build their restaurant close to their newest hotel, Lindesnes Havhotell, in the sheltered waters of a bay adjacent to the village of Båly. Committed to the plan, the Ubostads then approached a firm with greater international renown, Oslo and New York City-based Snøhetta, to design the restaurant’s interiors and to give notes on the overall design.

A daylong workshop in Snøhetta’s Oslo’s offices, however, yielded an unexpected result: the firm took over the entire project. Snøhetta co-founder Kjetil Trædal Thorsen didn’t flinch when confronted with the idea of an underwater restaurant, even if the premise seemed outlandish to many. Having built Egypt’s Bibliotheca Alexandrina and Norway’s Oslo Opera House, both of which intersect bodies of water, Thorsen knew Snøhetta had the right experience; it made them confident that they could successfully lead the project. “We’ve done so many things like that, where buildings converge with landscape, that we don’t think, ‘oh, it’s a difficult task,’” says Thorsen, “Instead, we think, ‘oh, that’s a great idea!’” Snøhetta’s co-founder, Craig Dykers concurs: “There’s an intriguing relationship we’ve long explored with getting to the edge of things.”

Dykers and Thorsen both note that the project is less about new engineering innovations and more about using architecture to foster greater intimacy between humans and nature. Norway, they point out, has a long history of building industrial structures that clash with the elements, and the technical blueprint for Under isn’t so different from those used for offshore oil-drilling platforms.

Rune Grasdal, an architect at Snøhetta and the project manager for Under, says the firm’s first critical edit of the original design involved moving its location entirely. “It was, at first, too close to the hotel,” he says. “We placed it directly in the sea, in a more rough situation.” Ubostad says that storm swells around the restaurant can reach 10 feet or more.

“We wanted to make a building to withstand the forces of nature,” Thorsen says, adding that Under’s concrete walls are nearly three feet-thick and will eventually develop a patina whose texture and color will be altered by erosion. Grasdal says one inspiration for the restaurant’s exterior were the abandoned World War II bunkers he’s observed dotting the Norwegian coastline and “the way they’ve blended back into nature.”

Snøhetta also revised the project’s overall shape, changing it from a glass cube to something that looks more organic, and perhaps marooned, on Norway’s rugged coastline. The restaurant ultimately took the form of a tilted, concrete rectangular tube, partially submerged and partially breaching the surface of the North Sea. It’s separated from the mainland by an almost 40-foot-long bridge; diners must cross it to enter and exit Under as if walking a gangplank.

Once inside, guests will pass through a foyer, descend an oak staircase to a mezzanine-level champagne bar and finally follow more stairs to find their seats at Snøhetta-designed tables, sixteen feet below sea level. There, they’ll face the restaurant’s 36-by-11-foot acrylic picture window with a view of an ever-changing abyss.

“The project is bigger than a restaurant,” says Thorsen. “Part of it is allowing people to have a deeper relationship with the ocean,” adds Dykers. “Humans are mostly made up of water. We’re tremendously connected. Being in the restaurant will take us back to our ancient history.”

Theories of evolutionary biology aside, Under does have scientific aims. Trond Rafoss, a marine biologist with the Norwegian Institute of Bioeconomy Research, was hired by the Ubostads four years ago to start surveying the waters around the restaurant, both to better understand the lives of local species and to draw marine life into Under’s range of visibility, which will vary daily. “I still check the area every night from my smartphone to see what’s swimming around,” Rafoss says, having installed underwater cameras at Under’s location a year ago for just such a purpose.

Rafoss says he’s thus far treated the restaurant like an underwater research base, giving him ample time to study marine life in its natural habitat. “You can’t do that as a diver,” he says, “you always have to come up for air.” His access has afforded him views of phenomena he believes few if any scientists have witnessed. “We’ve seen 5-millimeter-long lobsters climbing the windows that people don’t ever see until they’re 5 centimeters long,” he says. “I’ve seen species of jellyfish I’ve only previously read about.”

Rafoss has also conducted a series of experiments with flickering lights and sound, aimed at attracting marine life toward the restaurant. “There’s been leppefisk, which is a kind of wrasse, pollock, cod, jellyfish and mackerel,” says Ubostad. Rafoss says that in order to keep the window clean so diners can see the fish, he sends down two divers twice a week to brush away microalgae and seaweed. “We tried a robot once,” Rafoss says, “but it didn’t do a good enough job.”

While the windows will be routinely cleaned, the plan is for the outer walls to be harvested. Small marine creatures like limpets, a type of snail, have affixed themselves to the algae-coated concrete. They’ve already become a favorite ingredient of Under’s 32-year-old Danish head chef, Nicolai Ellitsgaard, who has spent the last two-and-a-half years developing his menu while tirelessly exploring Norway’s southern coast. The first of Ellitsgaard’s 18 courses will look like a living limpet in its fluted, conical shell, but the plated shell will actually be made from seaweed and potato; inside will rest a mousse made from limpet meat from Under’s surrounding waters and parsley. Ellitsgaard plans to add limpets harvested from Under’s walls in future menus.

The profile of Under’s opening is elevated further by its geography. Scandinavia now sets a benchmark for avant-garde cuisine rooted in regional traditions and hyper-local ingredients and Ellitsgaard—who for five years ran an acclaimed kitchen in Norway (at the now-shuttered Måltid) but isn’t yet himself a player on the culinary world stage—has felt extra pressure to measure up.

In the hope of one day being ranked amongst the Nomas and Maaemos of the world, Ellitsgaard has sourced more than two-dozen varieties of seaweed, several of which which will be used throughout Under’s menu, including dessert. He’s become partial to a species of local stone crab that he says is eight times smaller than Norway’s famous king crab but far more intense in terms of flavor and sweetness. Ellitsgaard forages regularly for Vertebrata Lanosa, a type of red algae he says tastes like black truffles, and has been curing ling roe to use in dishes alongside both spring and summer vegetables.

Grasdal says no project in his 19 years at Snøhetta has ever generated this level of interest. And Ellitsgaard admits thus far the attention has mostly been on the architecture. “I’m lucky we’re booked,” Ellitsgaard says. “Nobody really knows anything about the food yet.”

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You enter by gangplank, and the concrete walls are three feet-thick. But for Norway’s Ubostad brothers, the challenge of constructing an underwater restaurant was part of the allure: “People around here think of what’s possible rather than what’s impossible.”

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