A 1963 book describes the Geophysical Event that ended the last civilization, and the CIA's copy was only released in 2013 as a "sanitized" version.
In The Adam and Eve Story, Chan Thomas says Earth's crust slides over its molten layer and the poles roll almost to the equator in less than a day.
The atmosphere doesn't move with the shell, so the land is hit by winds of about 1,000 mph, faster than the speed of sound.
Then the oceans pull back and return as "a mountain of water more than two miles high," crossing a whole continent in about three hours.
That wall would stand about six times taller than One World Trade Center.
According to Thomas, the wind and flooding rage for six days and nights, and almost nothing of our cities survives.
I simulated what that would look like hitting New York.