On a March evening in New York, inside the Rizzoli bookstore in Midtown, two architects from Milan — Stefano Boeri and Francesca Cesa Bianchi — sat down to talk about trees. Not parks or gardens, but forests growing inside cities, on buildings and among people. They were there to present Bosco Verticale: Morphology of a Vertical Forest, a book that traces the life of Milan’s now-iconic Bosco Verticale.

Part photo archive, part manifesto, the volume reflects on how a pair of residential towers covered in trees — once seen as a green stunt — helped reframe the conversation about urban living. When the project launched ten years ago, a forest in the sky felt more like fiction than architecture. Now it’s referenced across continents, so what changed? “We didn’t build a green building,” Boeri said.