Graham Hancock's "Magicians of the Gods" makes a good case for the demise of prior civilization's demise at the hand of comet fragments. Other than that there are at least one scientific study backing up comet fragments as bringing on the end of last Ice Age as well as beginning the Younger Dryas period, Origin of the Carolina Bays
From several years ago if you can find it: A RE-EVALUATION OF THE EXTRATERRESTRIAL ORIGIN OF THE CAROLINA BAYS* by J. Ronald Eyton & Judith I. Parkhurst
A New Paper on the Origin and Evolution of the Carolina Bays
There are others as well.
Apparently the Egyptians at the Luxor Temple carved the Ramses figures with machine precision that we could not duplicate 50 years ago and perhaps not even today, according to measurements recorded by Dunn in his Lost Technologies book. Whatever machines they use are long gone, but there is no way to make them using the primitive tools attributed to have been used used by the Egyptians.
If you have not read it already, by all means get the book Sunken Civ has frequently recommended: “The Cycle of Cosmic Catastrophes (Flood, Fire, and Famine in the History of Civilization)” by Firestone et al. It’s main focus is about what stopped the warming from the Ice Age about 13,000 ya. A lot of scientific data there.