This completely blew my mind. Apparently the eruption of the Krakatoa volcano in 1883 was extremely loud. So loud, in fact that it could be heard 3000 miles away. When we think of how something that loud would effect humans, loss of hearing would probably be the first thing to come to mind. That's not the only thing that would have happened, though. The sound pressure alone would have rendered people (within 100 miles) unable to see or breathe. Absolutely unbelievable. Read more here.