Free exhibitions are held at this special collections library, occupying a National Historic Landmark brownstone building designed in 1845. Curiously, also on display is Napoleon Bonaparte's death mask – part of a collection of pieces donated to the Athenaeum by Joseph Bonaparte. Joseph, Napoleon's elder brother, and the former King of Spain, lived in Philadelphia for a while.
The research library, which holds a significant collection of architectural drawings, photographs, maps and rare books on architecture and design history, is also free.