Visitors to Lower Main Hall, SIB, by Unknown (Thomas W. Smillie?), 1867, Smithsonian Archives - History Div, Looking east of a newly decorated Lower Main Hall, or the Great Hall, of the Smithsonian Institution Building, visitors pose in the center. The second floor galleries are clearly visible. The delicate stencil work on the ceiling is by architect Adolf Cluss, who following the repair of water damage in the Lower Main Hall, used the opportunity to enhance the walls and ceiling..