>>2620170The city of Enoch, and everything else was destroyed in the flood. Even so, the people still lived to over 400 years old for the first few generations after the flood.
Only the memory of all the knowledge gained by Noah's family during that first age remained in the post-flood world.
The flood, and the subsequent tower of babbel, mark the beginning of archaeological history.
This is why the ancient civilizations of Egypt, Sumeria, and China all trace their history to about 5000 years ago.
After the tower, they retained a bit of knowledge of the old world.
https://www.youtube.com/watch?v=DA-AkJzpKmg 
