Well I heard that about a year ago a coalition of archeologists and scientists from Central Europe were excavating near the northern Atlantic coast. A few miles out where there are some mountains(underwater of course). They mainly wanted to attempt to uncover traces of old civilizations from around the Sumerian age or before. I guess after a tsunami or earthquake smaller artifacts started showing up. I guess that was enough to get their attention. They managed to uncover some tombs built near the peaks of these mountain that were surprisingly well intact and not even completely flooded. The tombs had a few dozen well preserved mummies that were covered in golds and silvers. A few of these mummies were buried with tablets and parchments depicting the likes of dragon gods. Now this civilization further supports the idea of the existence of Atlantis also existing farther into the now North Pacific Ocean. Back on topic, they buried these people the highest they could up the mountains because their dragons gods supposedly lived atop them. Now I say dragons, but of course they referred to them as flying serpents. They spoke pretty similar to the Sumerians so they must have been a Sumerian civilization that branched off or perhaps, they were the originals, and the others branched off. It took a while for them to extract everything and then study and translate but I'd say they did a good job. Time-wise it appears that there was a small window of time where the Earth was still able to support creatures of that magnitude and humans. I'd say about 40-50,000 years ago. The way they depict these things is in the realm of possibility. They were pretty well feathered but not entirely. They were also about the size of of a T-Rex. Turns out that that civilization was already using bronze metals so they were fairly advanced. Scholars believe that either the dragons wiped them out(save the ones that fled)or the Earth's change did. Really interesting stuff.