The museum's National Mall building construction began in mid-1983. The project, which also included the Sackler Gallery for the Smithsonian's Asian art, created 368,000 square feet of exhibition space at a cost of $73.2 million, half of which from the federal government. Almost all of this room was created underground so as not to affect the quadrangle's landmark Smithsonian Institution Building (the Castle), its greenery, or its view. The Smithsonian Castle hides the museum and South Quadrangle from the National Mall, which has contributed to the museum's lower attendance compared with other Mall attractions. The quadrangle project's design architect was Jean-Paul Carlhian of Shepley, Bulfinch, Richardson & Abbott, based on a concept by Junzō Yoshimura. The two new museums had little involvement in the architectural designs, which were drawn in the 1970s prior to their arrival.