Now we know that man is more than two million years old,' exlaimed Heyerdahl, 'it would be very strange if our ancestors lived like primitive food collectors for all that time until suddenly they started in the Nile valley, in Mesopotamia and even in the Indus valley, to build a civilization at peak level pretty much at the same time. And there's a question I ask that I never get an answer to. The tombs from the first kingdom of Sumer are full of beautiful ornaments and treasures made of gold, silver, platinum, and semi-precious stones -- things you don't find in Mesopotamia. All you find there is mud and water -- good for planting but not much else. How did they suddenly learn -- in that one generation just about -- where to go to find gold and all these other things? To do that they must have known the geography of wide areas, and that takes time. So there must have been something before.