It's pretty egotistical to think that we're the only "advanced" civilization since the ice age, this planet has been able to sustain life for hundreds of millions of years, that is undisputed add to that the fact that in the last 100 years our technological advances have been great and it leaves me thinking, what if....what if there was a far more advanced civilization than ours and they got wiped off the map by a cataclysm leaving few pockets here and there with survivors.....it will happen again, let's say it happens today, 95% of life as we know it gets wiped out, out of the 5% remaining...how many are capable of surviving the chaos, certainly won't be city slickers, the best suited people to survive are those in remote areas living off the grid, our technology wouldn't mean fluff and wouldn't get carried over to next generations... repopulate with survivors.
The entire issue with a previously more advanced civilization on our planet is that there is no material or measureable evidence.
We can find caveman drawings from 18000 years ago, but we can't find some advanced technology remains from whenever this civilization may have existed?
We can find fossils of all kinds dating millions of years. But we cannot find one fossil that shows any evidence of advanced civilization?
What, did they made space crafts out of wood or something?