The 12,000-seat Swiss Life Arena may look unapologetically boxy when approached by rail or road. Up close, however, it is enormously fun—not an adjective often associated with the London and Zurich-based practice Caruso St John Architects. Known for architecture that is as intellectually rigorous as it is aesthetically sensitive, the firm’s work often resolves in a commitment to context, be that in a topographical way—as with the Nottingham Contemporary (2009), which superbly marries the engineering of an elevated tramway with the geology of a hill—or in structural expression, as with the St. Jakob Foundation (2018), where balconies play visual games with the historic viaduct immediately adjacent.