Whispering acoustics of the Jefferson Memorial

The domed interior of the Jefferson Memorial produces a whispering-gallery acoustic effect: faint sounds made against the inner wall can often be heard on the opposite side of the rotunda. The phenomenon is commonly demonstrated by visitors and noted in guidebooks as an architectural curiosity of the memorial, which opened in 1943. The effect arises from the memorial's circular colonnade and dome geometry rather than any supernatural cause, but it has become a piece of local lore and a frequent visitor attraction.