12 Oceanix Busan

For reimagining what—and where—a city can be

As the world searches for ways to create more resilient coastal communities, UN-Habitat, the Busan Metropolitan City and U.S. sustainable tech firm Oceanix have unveiled a peek into the future. Designed as an extension of the South Korean port city of Busan, the ultra-modern, endlessly adaptable prototype is loaded with all sorts of eco-friendly features. There will be ample solar infrastructure, a closed-loop water system, greenhouses that expand and contract based on need, and extensive public spaces to foster a sense of community for its 12,000 residents. But it’s just as notable for what it won’t have: land beneath its surface. 

Instead, the prototype is “a buoyant, modular city block with the potential to scale indefinitely,” says Alana Goldweit, Oceanix project designer and an associate at BIG, which co-led the design with Korean architecture studio Samoo. 

A 15.5-acre (6.3-hectare) trio of interconnected floating platforms—one for housing, one for public spaces like schools and one for R&D—will connect to the mainland by link-span bridges. The platforms, hollow and coated with limestone, are designed to trap air underneath, aiding in flotation. Cages will be built into the undersides to attract marine life and encourage coral reef growth, as well as to allow inhabitants to easily harvest scallops and kelp. And as the city grows, the prototype’s three platforms could expand into a honeycomb of dozens, ultimately supporting some 100,000 people. 

“We developed Oceanix to be fully sustainable and autonomous, and the more we expand the more we can add features—a hospital, police, fire stations, religion centers—to support and serve the inhabitants in the same way a neighborhood would,” says Matteo Pietrobelli, chief systems engineer at Oceanix.

Although the prototype was unveiled in April, Oceanix initially proposed a floating city concept at a 2019 United Nations roundtable. In 2021, Busan signed on to “scale this audacious idea,” in the words of Mayor Park Heong-joon. “Our common future is at stake in the face of sea level rise and its devastating impact on coastal cities,” he said at the announcement.

The long list of global project partners that joined the effort underscores the urgency—and complexity—of the undertaking: Prime Movers Lab, Arup, Bouygues Construction, Helena, the MIT Center for Ocean Engineering, the Korea Maritime & Ocean University, Studio Other Spaces, Wärtsilä, Transsolar KlimaEngineering, MIC-HUB, Sherwood Design Engineers, Agritecture, the Center for Zero Waste Design, GreenWave and the Global Coral Reef Alliance. 

The U.N. estimates that 2 out of 5 people on the planet live within 100 kilometers (62 miles) of a coast, and that 90 percent of megacities worldwide are vulnerable to rising sea levels made worse by climate change. Building atop the tides offers an alternative to fighting them. Yet turning that big idea into reality means meeting risks head-on. 

“Dealing with the waves is one of the most complex and challenging parts of the design process,” says Pietrobelli. “To be livable, inhabitants must not be able to perceive the movements of the platforms, and we needed a structure that had the same performance no matter the direction of the waves.” 

Hydrodynamic analysis enabled the engineering and design teams to model how the platforms would react to various wave and wind scenarios, tracking both vertical and horizontal accelerations and iterating the designs to minimize movement while ensuring the structures could withstand waves that might be kicked up by a 1,000-year storm. To lessen lateral movements, a mooring system connects the platforms to the seafloor. “Even when you have the highest waves, it’s almost as if you are on land,” Pietrobelli says. “Nobody’s going to feel sick on it.”

For all the design and engineering challenges the team worked through before unveiling prototype designs, Oceanix co-founder Itai Madamombe minces no words about the value of having a forward-looking sponsor: “You need a credible government leader that is deeply committed and bold to take on the future,” she says. “The Metropolitan City of Busan has the maritime engineering capability to realize this bold mission and is completely focused on the future. We’re aligned in purpose, and that helps stay the course of such a complex and multifaceted project.”