There has been much research published lately that describes, in detail, an explosion of extra terrestrial origen that wiped out North America about 12,900 years ago. But where did it happen? The answer is that the site of the Pleistocene/Holocene comet impact event some have described has been right under our feet all along. But the stupendous size of the thing is almost beyond comprehension. And that is why we never realized what we were standing on. And until we saw Shoemaker-Levy 9 hit Jupiter, it would have been incomprehensible that such a thing could possibly happen at all. The story of finding it is a lot like the ancient story of the blind men and the elephant. The blind man who feels a leg says the elephant is like a pillar; the one who feels the tail says the elephant is like a rope; the one who feels the trunk says the elephant is like a tree branch; the one who feels the ear says the elephant is like a hand fan; the one who feels the belly says the elephant is like a wall; and the one who feels the tusk says the elephant is like a solid pipe. And then someone explained to them: All of you are right. The reason every one of you is telling it differently is because each one of you touched the different part of the elephant. So, actually the elephant has all the features you mentioned You see, all of this time we've all been like the fleas on an elephants back, who, when asked what they were standing on, replied; "Why, this is our world of course!" The scars left by a billion megaton explosion that devastated an entire continent shouldn’t be that hard to spot, should they? Not aftter only a few thousand years anyway. As it turns they are as plain as day for all the world to see. We just needed to get a little distance. Simply turn on Google Earth (not Google Maps it's too slow) set it to the highest resolution you can get, open your eyes, then zoom out to about 1300 miles, and then look closely at the eastern USA. If you know some one who has military experience with aerial surveillance photos have them look with you. The two circles you see centered on north central Alabama are not mere artifacts of the software. I believe they were caused by the compression waves of rapid, multiple explosions of unimaginable magnitude. And that they are the ghostly signature of the beginning of the Pleistocene / Holocene extinction. The explosions didn't cause a crater in the normal sense. But it could be confused as one if you don’t look close enough. Careful analysis of sedimentary deposits all over North America on will give results that are consistent with a large exploding comet about 12,900 years ago.. The circles are approximately 250 miles in diameter and are part of a compression wave structure from an above ground explosion a billion times more powerful than Tunguska, and should not be confused as the rim of a crater at all. The comet fragments look to have exploded in the air like the Tunguska event. But it was a rapid series of objects 2 to 4 miles in diameter exploding above ground. And each explosion was so powerful that they broke the very bedrock and left a giant compression wave frozen in the earths crust like a ripple in a pond. And at the center you’ll find a fracture star like a stone fracture in a windshield. But this one is 12 miles long and 6 miles wide. And the town of Marshal Alabama is at the center of it. There were other fragments too, and if you look closely you can see their footprints in the perfect circular depressions 30 or 40 miles wide around and near Marshal. The other major explosion left a circular impression 65 miles wide, with another set of compression waves centered on eastern Tennessee and with a splash curtain extending over 400 miles to the northeast. The amazing thing is that as incomprehensible and fantastic as it may seem that such an immense impact structure could be real, and that it has been under our feet all this time, the explosion that caused it is precisely what is described in exquisite detail by R.B. Firestone etal. In their research entitled: Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. And in another paper by C. Vance Haynes Jr. Departments of Anthropology and Geosciences, PO Box 210030, University of Arizona, Tucson, AZ 85721 Entitled: Younger Dryas ‘‘black mats’’ and the Rancholabrean termination in North America Dennis Cox P.S. I have both of the papers mentioned above in PDF format for all who may be interested.