The McCormick Tribune Campus Centre seeks to reinvigorate the urbanism inherent ? but long since neglected ? in Mies van der Rohe?s 1940 masterplan for the Illinois Institute of Technology. The large single-storey Campus Center provides a focal point for the previously sundered halves of the campus, and features a noise-absorbing steel tube wrapping the Elevated metro that runs directly over the building and, inside, a dense mosaic of programs including a bookstore, food court, caf auditorium, computer centre, and meeting spaces.How to energize a campus that has half the population that animated it in the 1940s but now double its original footprint? To us, the conundrum implied a building that is able to re-urbanize the largest possible area using the least amount of built substance.To create a new point of density for the campus, we located the building at the heart of IIT ? a large rectangle between State and Wabash, 32nd and 33rd streets ? and directly underneath the ?L?, the artery that connects the campus to the rest of Chicago. By enclosing the tracks above the Campus Center in a muffling stainless steel cylinder, a formerly deafening no-man?s-land becomes a not only tolerable but a magnetic environment. The encircled track ? known among students spontaneously as the Tube ? becomes a crucial part of the Campus Center?s, and IIT?s, image.Rather than stacking activities in a multi-storey building, we opted to arrange each programmatic element of the Campus Center in a dense single plane that would foster an urban condition. To achieve this, in 1997 OMA carried out a study to map the ?desire lines? of student foot traffic across the campus. These intersecting diagonal paths are maintained inside the Campus Center itself, linking the multiplicity of activities via a network of interior streets, plazas, and urban islands that form neighborhoods: 24-hour, commercial, entertainment, academic, recreation, and other urban elements in microcosm. The unifying element of the Campus Center is the roof: a sloping concrete slab that protects against the noise of the L while encompassing the heterogenous programs below. Where the roof ducks beneath the ?L?, the underside of the the Tube juts through the concrete as a reminder of what?s above. The roof has a long overhang that embraces the adjacent Commons Hall, Mies?s original student centre, designed in 1953. The Commons has its original perimeter and interior wooden partitions preserved, and now functions as a food court.