[1] It is not usually open to the public, due to security concerns, though occasionally special tours are organized.

[3] This comprises approximately 40 percent of the Smithsonian's collection which is not on display, while the rest of the objects are housed behind-the-scenes in the museums themselves or at other off-site storage facilities.

[4] The collections are housed in five numbered buildings, called "Pods," each about the size of a 3-story-tall football field.

[3][2] Notable features include "enormous tanks for cleaning whale skulls, chambers to preserve Antarctic meteorites, art from throughout the ages, and a botany collection with five greenhouses.

[3] In its laboratory and office areas, the MSC houses the Smithsonian's Museum Conservation Institute (MCI), the Laboratories of Analytical Biology (LAB) and other numerous departments from the National Museum of Natural History, including the Department of Anthropology, the National Anthropological Archives (NAA), the Human Studies Film Archives (HSFA), the Walter Reed Biosystematics Unit (WRBU), as well as branch of the Smithsonian Institution Libraries.