[cripplecreek]

seems like a civilization would have a pretty limited time frame to build something like that. It’s been under ice or under water for the better part of the last 50 or 60 thousand years.

[muawiyah]

The ice was pretty much out of the area 14,000 years ago. Then it came back, kind of, with the Younger Dryas, 3,000 years later.

That's plenty of time for human beings to have built all sorts of things.