Pavilion showing unobstructed corner of cantilevered roof at left; support column at center; The Neue Nationalgalerie (dedicated to art of the 20th century) was opened in 1968 and is the last major construction completed by Ludwig Mies van der Rohe. The architect’s long-term preoccupation with creating fluid, open spaces culminated in the design of the glazed upper pavilion of the gallery (most of the museum is on an underground level). The upper story serves as an entrance hall as well as the primary special exhibit gallery, totaling 2,683 square meters of space. It is elevated from street level and only accessible by three flights of steps. Though it only comprises a small portion of the total gallery space, the exhibition pavilion stands...