https://www.youtube.com/watch?v=88XunzrMjts
What might have happened hundreds of millions of years ago? If ancient hightech civilizations crashed and burned, how would anyone know about it today?
536 AD: The Ancient Climate Catastrophe That Crippled The Globe https://www.youtube.com/watch?v=cKUz5Vjq9-s
Things occasionally happen that can wipe out various civilizations.
Elon Musk Tells What The Navy Saw While Diving in the Ocean https://www.youtube.com/watch?v=al1VZh4_FEk
