After any large cataclysm, the previous civilizations are all but undetectable. Only stone and glass tend to last more than a few hundred years. Most plastics and steel will easily be eradicated absent constant maintenance. I believe the Flood happened and the civilizations prior to it were very high tech. Mankind lived almost 1000 years pre-Flood and had larger brains.

I could do a lot in 1000 years with double air pressure, higher oxygen content, and very smart ancestors who were still alive. Noah was 500 when he began to build the Ark. It took him 100 years of enduring constant ridicule and hatred to build it, then it started raining for the first time in history and did not stop for 40 days.

The Days of Noah are here again... evil on the rise and the ability to modify genetics at will. I wager we have less than 50 years of this Age left.