Cities at sea, afloat on the waves, have long been a cherished dream for forward-thinking architects and science fiction writers. Now the world’s first fully floating community is set to take shape in the turquoise waters of a Tahitian lagoon.

Blue Frontiers, a Singapore-based start-up, has signed a memorandum of understanding with the French Polynesian government to build a $60-million floating village on the south side of the main island of Tahiti, with a prospective starting date of 2020.

The village will serve as a showcase and test bed for technologies that will be needed to create much larger floating communities, says Joe Quirk, president of the Seasteading Institute, a San Francisco-based nonprofit that is the driving force behind Blue Frontiers. The institute hopes one day to establish full-scale floating cities that could flourish outside the territorial waters of existing nations.

Tahiti’s floating village will be just inside the island’s protective coral reef, in water about 100 feet deep some 1,000 yards from shore. Plans call for 200 to 300 people to live and work there on a dozen or so floating platforms, each about the size of a baseball diamond. The platforms will be connected by walkways into a combined area of 7,500 square meters.

Quirk says he expects the floating village to thrive through a combination of eco-tourism and new aquatic industries like seaweed farming and wave power.