Sheltered by the arched portico, the museum’s front wall consists of a two-story curtain of glass windows with bronze mullions. Johnson wrote that this curtain wall separated “the art from the city, the cool from the warm, the peaceful from the active, the still from the windy.” The main entrance leads directly into a two-story hall of Texas shellstone, dark extruded bronze, rich brown teak, and a floor of pink and gray granite. Beyond the main area, Johnson designed five intimate galleries of equal size for the display of art. On the mezzanine level, he placed five similar rooms for a library and offices; today they serve as galleries for rotating exhibitions, each with a balcony that looks out over the main hall. The latter space provides a grand, yet serene, setting for works of sculpture and large paintings. Although the museum was initially conceived as a small memorial structure, its collections grew rapidly, and the institution soon required additional space. In 1964, only three years after the museum first opened, a 14,250-square-foot addition was completed to provide space for offices, a bookstore, a research library, and an art-storage vault in the basement. Joseph R. Pelich (1894–1968), an associate architect of the original building, carried out the work and consulted with Johnson to assure consistency with the original architectural vision. The museum opened yet another addition, designed by Johnson and his partner, John Burgee (b. 1933), in 1977. It expanded the museum’s area by 36,600 square feet, more than doubling its original size. The three-story section, which came to a point at the junction of Camp Bowie Boulevard and Lancaster Avenue, included more office space, a two-story storage vault, a greatly expanded library, and a 105-seat auditorium.