I have it on good authority that if you stand very still and the rotunda is really, really quite you can hear the slightest of tapping noise coming from the coffin of GHWB:
.-. . .- -.. / -- -.-- / .-.. .. .--. ... / -. --- / -. . .-- / - .- -..- . ...
My reliable source says it sounds like Morse code. Copy the string of tapping noises above and follow link below...paste into translator.