Sometimes, you need a little peace and quiet to stay sane. But it turns out too much quiet can drive you crazy- or at least make you hallucinate. That's what scientists at Orfield Labs in Minneapolis have found by studying how subjects react in their anechoic chamber, also known as the world's quietest room. The sound level in the room, which actually has the Guinness World Record, is -9 decibels, compared to the average "quiet" room's 30, according to MPR News.

The key to the level of silence is the fact that the walls, floor and ceiling absorb all sound, rather than reflecting it, as most surfaces do. Thus the term anechoic: no echo. It's so quiet, you can hear your own organs: your heart, stomach, even your ears, which make a tiny amount of noise. It turns out that it's not an especially pleasant experience, especially in the dark. The longest anyone has ever spent alone in the chamber? Forty-five minutes.

Orfield Labs uses the anechoic chamber to test the noise levels of various products like LED lights. But watch out: it could easily become a place to drive people mad.