The Smithsonian is a large national museum in Washington DC.
At some point between 2009 and 2033, the Smithsonian opened up an exhibit about the Einstein-Rosen bridge and the three men who invented it. ("CS:Origins") Part of this exhibit involved ROSS, an AI built by Dr. Shelton, who was trapped in a closed network and allowed to converse with visitors via the radio-flashlight.
Florence Brennan visited once before 2029, where she learned Shelton's location in Glencoe and attempted unsuccessfully to bust ROSS out. Because of this she was barred from ever entering the Smithsonian again.