Percy Jackson, Mythology, and Conspiracy Theories

So, I recently read the first book in Rick Riordan's series of Percy Jackson books, The Lightning Thief. It was decent. The plot was dumb, the characters were ok, but the idea was brilliant. I loved it. (If you're unfamiliar with it, the Percy Jackson/Heroes of Olympus books are based on the premise that the Greek gods from popular Greek mythology are still out there, but instead of being in ancient Greece, it's modern, 21st century America, and the gods are still running around fighting and messing things up and making single moms all over, like they did in the Greek mythology. Which makes it a little ironic that the book is meant for like junior-high level/age 13-14 kids, but whatever.) 

Anyway, what's cool is that the idea actually holds together; normal humans are blinded (as they were in the Iliad) by a mist over their senses and minds that causes them to reinterpret everything supernatural that they see and don't believe. The gods are described as the driving force in the westernization of civilization, which is why the height of civilization has gradually progressed from Greece to Europe to America over the years. The constant stream of demigods have become this nation's heroes, etc (it doesn't, sadly, go into a lot of detail on this, but there are references like "you realize that only Orpheus, Hercules, and Houdini have ever gotten back OUT of Hades alive". It's just cool.)

ANYWAY, that got me thinking about Greek mythology, and I remembered how many cultural mythologies -- a surprising number, really -- have stories that are similar to some events in the Bible, most prominently the Flood. Quite a few (including Greek) cultures have stories of an epic flood, and there are other examples of this too, but of course most of popular mythology has to be pretty much completely made-up, right? We don't (and didn't) have superhuman beings (the Greek gods were not, in the strict sense, gods) running around, right? 

Or do we?

Here's Genesis 6 (ESV):

 When man began to multiply on the face of the land and daughters were born to them, 2 the sons of God saw that the daughters of man were attractive. And they took as their wives any they chose.

Sound familiar?

Most prominently, it's clear that since this was before the Great Flood, any descendants of this would have perished in it, and so don't survive to this day. RIP. 

And I'm not advocating this as a serious position. We really have no clear idea what this Genesis passage is referring to, in any detail. (There are crazy conspiracy theorists who believe that (something like; i disremember all the details) the race of Nephilim were descended from this and are still around us today, but I forget. It was wacky.)

But isn't that something of a kinda interesting thought? It doesn't seem to be completely unfounded. I mean, like I said, 1) we have no way of knowing, and 2) it really doesn't matter. Yet as I pointed out, there are many cultures with flood myths, which are based on truth. Is it completely crazy to suppose that some of the other myths might be based on truth as well?