@jcboy,
Now, don't accuse me of being a doomsayer, but did you see the special on one of the History or NGO channels? Catch it if it's repeated, and it lasts 3 hours.
It seems the Egyptions quit building pyramids rather abruptly all those centuries ago, from lack of water from the Nile that would float the huge stones to the site for building. Since they also relied on a flood each year to fertilize the entire land and provide water for just about everything, they lost any and all ways to grow food, feed the animals, etc. In short, they had no way to live.
After much (incredibley much) researching and digging archeologists have found that a drought in the area lasted for "a generation."
Egypt was built along the Nile River, everyone knows, and there was nothing except desert in any direction. Evidence has shown that these people ended up eating all animals, and probably each other.
Well, that's not so scary for us today, but they now have discovered that the same drought occurred all over the world, at the same time. THAT'S scary.