Here's The World's Quietest Room
In this room, you can hear the motion of your head when you turn it and your bones make a grinding noise when you move.
It is rumored that if you spend too long in there with the lights off, you may go insane. But that is just a myth. However, the effects of the silence become overwhelming the longer you stay.
An average quiet bedroom for example will usually get a dB reading between 25 and 30 but the noise of this room is negative 20.3dBA, which is far lower than the threshold of human hearing at 0dBA..