Hard To Believe -

: While the Great Pyramids were being built in Egypt, woolly mammoths were still roaming the earth on Wrangel Island; they didn't go extinct until about 4,000 years ago.

: Human stomach acid is strong enough to dissolve a single-edged razor blade in about two hours.

: An average white, puffy cumulus cloud can weigh over one million tons—roughly the weight of 200,000 elephants. Impossible Survival & Human Oddities 17 Wild And Hard-To-Believe True Facts - BuzzFeed