The World's Quietest Room

Staying in a cabin in Newfoundland was pretty quiet...except early in morning when the truck drivers started their day lol. When i say i could hear my hair grow is no exaggeration lol. I can imagine being in a sound proof room or a total sensory deprivation situation could seriously mess with people.
 
A friend of mine has tried those flotation/isolation tanks. He said his lesson learned from his first session was to not go in hungry. He said the sound of his stomach growling for nearly an hour was amazingly loud and distracting.
 
This would be fun to try.