People don't realize that just 8000 years ago, you could walk from britain to continental europe as it was connected by land to europe.
https://en.wikipedia.org/wiki/Doggerland
It's amazing how in a short period of time ( in geological terms though it seems like a lot of time for us ), how much of the earth changed.
Another interesting tidbit, we had a little ice age not too long ago which ended in the mid 1800s.