The dictionary of the Royal Spanish Academy says that an infrastructure is an underground work. If this is so, then the future multimodal transport hub and shopping center of Gangnam, right in the heart of Seoul and called Lightwalk, is literally one. Dominique Perrault and the South Korean firm Junglim have together won the competition in which the French architect has again tackled a theme that has been obsessing him for several years now: buried architecture. With its size resembling an airport’s and its upper green plaza, the Ganghan International Transit Center follows in the wake of similar Perrault works, such as Plaza Garibaldi in Naples or Ewha Womans University, also in Seoul.