The Mapparium's whispering-gallery

The Mapparium is a three-story stained-glass globe inside the Mary Baker Eddy Library, constructed in 1935. Visitors walk on a suspended catwalk through the interior, viewing a world map as it was in 1935. The glass sphere produces a pronounced whispering-gallery acoustic effect in which whispers and sounds at one point can be heard clearly across the interior. The installation is a documented architectural and acoustic curiosity and remains open to the public as an exhibit.