Regarding that Yonaguni structure, which certainly looks manmade to my untrained eye, is it carved rock? That's pretty sophisticated work - i doubt if i could do that myself with all my modern knowledge if left to my own devices.

There does seem a few too many accounts of uber flooding for it to just be a coincidence. Something was going on - whether that was one big thing or a series of smaller, different things, or all of the above, it's hard to know

Here's one of my favorites, from Kenya. It's really like the 'in-laws from hell'.

"Kikuyu (Kenya):
A beautiful but mysterious woman agreed to marry a man on the condition that he never ask about her family. He agreed, and they lived happily together until it was time for their oldest son's circumcision, and the man asked his wife why her family couldn't attend the ceremony. With that, the wife bounced into the air and made a hole seven miles deep when she landed. She called upon her ancestors, who came as spirits from Mt. Kenya. The spirits raised a thunder and hailstorm as they came. They brought food, goats, cattle, and beer with them and, while the people took shelter in caves, flooded the countryside with beer, turning it into a lake. When the spirits left, they took the couple and their children with them into Mt. Kenya. [Abrahams, pp. 336-338]"