While it's near the center of the museums on the National Mall in Washington, DC, the National Gallery of Art isn't a part of the Smithsonian Institution. The gallery opened in 1941 as a gift to the United States from the estate of Andrew Mellon. The modern angular East Building of the gallery, designed by I.M. Pei and also funded by members of the Mellon family, opened in 1978. An outdoor sculpture garden opened in 1999.