East Building, National Gallery of Art

The East Building of the National Gallery of Art in Washington, D.C., was designed by the architect I. M. Pei to house the museum's collection of modern and contemporary art and its study facilities, and it opened to the public on June 1, 1978. Pei resolved the building's awkward trapezoidal site by dividing it along its diagonal into two triangles, one holding public galleries and the other a library, offices and a study center, and the triangular geometry of the site plan recurs throughout the building's details down to individual floor tiles. At the building's center is a large skylit atrium, roughly 16,000 square feet, enclosed by sculptural concrete forms and clad, like the exterior, in Tennessee pink marble matched to the museum's earlier neoclassical West Building. The two buildings are connected underground by a passage called the Concourse, unifying the classical West Building and Pei's modern triangular addition into a single museum campus, and the East Building received a National Honor Award from the American Institute of Architects in 1981.