> Graham's arguments have strong merit - the presence of the myth of 'civilizing HERO coming from the water with a BOAT, teaching agriculture, infrastructure, civilization' in regions that are not known to have had any contact until modern age points to one of the below:

Here's a counterpoint: the main culture that's attached to is the Mexica, who immigrated into the Central Mexican Valley somewhere between about 1200 and 1300. This means that they were not involved with any of the flourishing developments of the Preclassical and Classical (or even much of Postclassical!) Mesoamerica--notably, not the achievements of Teotihuacan. Nevertheless, they did consciously adopt many elements of the existing cultures that they would come to rule, and the Aztecs themselves engaged in a fair amount of myth-building to tie themselves into the culture. What is to say that the idea of knowledge being specifically given to them by a foreign culture wasn't a conscious attempt to justify their overlordship of the prior inhabitants of the land?

> Based on that, indeed, a lot of the prehistoric monuments point to a certain date at the end of younger dryas, which these prehistoric cultures described as catastrophic, cataclysmic in their monuments in different parts of the world.

One of the problems with archaeoastronomy is that there are too many variables. If you want to memorialize the sun--do you choose an equinox or a solstice (which one)? Or, in certain latitudes, the day the sun passes directly overhead? The setting or rising position? Or maybe you want the moon, one of the visible planets, the milky way, an important star. Then you have procession of the equinoxes--if you don't narrow it down to within roughly a century, the alignment is off (a lot of dating is insufficient precision to give that tight a bound). You get extra slack for being only "slightly" off--ancient imprecision, amirite?--and besides, which features are you using to establish the alignment in the first place?

In short, you have so many parameters in archaeoastronomy that if you want to find an alignment, you probably can. So if a purported alignment is the only evidence you have of a theory... be very skeptical.

> Which also explains the differing flood mythologies that exist in totally isolated cultures.

I've never been impressed with the thesis that "flood myths = some cultural echo of sea level rise." The thing is that floods are a pretty common thing in... just about every climate (even deserts, which can be prone to flash floods), and so the concept of a flood that utterly destroys everything is going to be readily accessible to every culture. If you've got some cosmological need to have the world be utterly destroyed... a flood is probably the handiest option. (Props to, I think it was the Aztecs, who came up with a different way the world was destroyed after every cycle.)

> Graham seems to be the pioneer here. And the conservatism of modern scientific establishment, which descends from its scholastic roots that shaped in the shadow of Christianity that always prefers to explain history in a linear, developing fashion, shows itself again.

Arrrgh. If you ever take a class in anthropology, one of the first things you will likely learn about is the unilinear evolution model of civilization... followed very swiftly by how utterly wrong and out-of-date it is. It's not what the scientists believe, not for at least 70 years at this point. It is what popular anthropology believes, though, and people like Hancock are partially to blame for that.