The architect and structural engineer designed the Tower's curtain wall with a modernistic masterwork of glass and aluminum. The curtain wall system consists of bronze-tinted vision glass and black anodized aluminum spandrel panels captured in a striking black anodized aluminum framing. Granite panels, with aluminum-framed glass storefront windows, accent the ground level façade on the east, north and south building elevations. Building setbacks are provided on the building’s northwest and southeast corners at the 50th floor, the northeast and southwest corners at the 66th floor, and the north, south and east elevations on the 90th floor. The structural framing consists of steel columns and beams in a “mega-module” system consisting of nine modules. The foundation system consists of belled, reinforced concrete caissons with reinforced caisson caps. The Franklin Street entrance has a beautiful large glass, aluminum and steel canopy which was added to the Property in the mid 1990’s.

The Property’s impressive three-story lobby welcomes visitors and tenants with sculptor Alexander Calder’s Universe, a mobile of varied shapes, colors and movements suggesting the infinite potential of human creativity. Willis Tower lobbies are exquisitely modernistic, with transparent walls and escalators piercing the vertical space. The nearly $70 million lobby refurbishment in 1992 by DeStefano & Partners incorporated elaborate finishes and emphasized the sheer size of Willis Tower. The lobby is further characterized by polished granite flooring and travertine walls with stainless steel column covers. Soffit, column and ceiling mounted fluorescent, incandescent and high intensity lighting fixtures create a glowing well-lit environment. The main lobby of Willis Tower contains one entrance on the east side of the building and one entrance on the west side of the building. The Wacker Drive lobby serves as the primary entrance to the Property providing access from the street. The east entrance is accessed directly from Franklin Street.