After launching a home-sharing revolution, Airbnb’s founders started asking themselves, “What’s next?” They successfully created a global network of more than 5 million homes, castles, and treehouses for rent, and their business is worth an estimated $ 38 billion . But what else could Airbnb become?

It’s a question that led chief product officer and cofounder Joe Gebbia to start Samara, a futures division of Airbnb, in 2016, meant to develop new products and services for the company. Gebbia’s answer to what Airbnb can be next: architect and urban planner. Not just the company that provides the housing–the company that provides the houses.

Today, Samara is announcing a new initiative called Backyard, “an endeavor to design and prototype new ways of building and sharing homes,” according to a press statement, with the first wave of test units going public in 2019. In plain language, that means Airbnb is planning to distribute prototype buildings next year.

The name “Backyard” might imply that Airbnb just wants to build Accessory Dwelling Units (ADUs), those small cottages that sit behind large suburban houses and are often rented on Airbnb. Gebbia clarifies that is not the case. “The project was born in a studio near Airbnb headquarters,” he says in an interview over email. “We always felt as if we were in Airbnb’s backyard–physically and conceptually–and started referring to the project as such.”

Backyard is poised to be much larger than ADUs, in Gebbia’s telling. Yes, small prefabricated dwellings could be in the roadmap, but so are green building materials, standalone houses, and multi-unit complexes. Think of Backyard as both a producer and a marketplace for selling major aspects of the home, in any shape it might come in.

“Backyard investigates how buildings could utilize sophisticated manufacturing techniques, smart-home technologies, and gains vast insight from the Airbnb community to thoughtfully respond to changing owner or occupant needs over time,” Gebbia says. “Backyard isn’t a house, it’s an initiative to rethink the home. Homes are complex, and we’re taking a broad approach–not just designing one thing, but a system that can do many things.”

As grandiose as that sounds–and ironic, given that Airbnb itself may be responsible for measurable increases in real estate pricing–there is a real need to rethink housing. The UN predicts the world will construct 2.5 trillion more square feet of buildings worldwide by 2060–which, as Gebbia points out, is the equivalent to another Paris every week. Buildings are environmental nightmares, too, contributing to 39% of CO2 emissions in the U.S.