Inside Fei-Fei Li’s $1 billion new AI company, World Labs

Walking into World Labs—the San Francisco startup cofounded by Fei-Fei Li, known in tech circles as the “godmother of AI”—visitors are met with a wall tiled in rainbow hues. A grand piano beckons at the end of the deep, sunlit lobby. Chair-size iridescent spheres rest against the walls, as if a giant forgot to pick up his toys. But around the corner, the walls and floor look scrambled, like a cubist painting left out in the rain. Luckily, this “world” is just a simulation of the World Labs lobby I’ve built using Marble, the company’s generative AI app. My real tour had taken place a week earlier at the company’s actual offices, where reality—including the rainbow wall, spheres, and piano—stayed mercifully intact. “Marble is the first part of [our] journey—it’s not a fully matured model,” CEO Li had told me, wearing a baggy maroon World Labs hoodie and settling her 5-foot-3 frame into a chair in a cozy wood-lined conference room. A world-renowned AI scientist known for her self-effacing demeanor, Li is being characteristically modest about Marble’s capabilities. The app, launched last November, uses a new type of AI called a “world model” to generate interactive 3D replicas of any space—real or imaginary—from visual or written prompts. These “worlds” can be anything, from floating castles and sci-fi vistas to, well, a certain startup’s entryway. My results were a little off, but Marble still conjured the whole thing in a matter of minutes from a few photos I haphazardly snapped with my iPhone. If you actually know what you’re doing, Marble’s world model can produce 3D environments rich and expansive enough to use in virtual film production, architectural design, and robotics training—all domains in which World Labs already has paying customers. Li won’t comment on current revenue or engagement metrics; one of the company’s cofounders, Ben Mildenhall, says that Marble is still in a “postlaunch discovery phase” after coming out of beta last November. World Labs offers