I started figuring this out years ago when I was researching ancient polygonal megalithic stone structures. A few researchers to note, Brien Foerster, Zecharia Sitchin, Graham Hancock, Ben at UnchartedX, Randall Carlson at GeoCosmic REX, Enigmas of the Ancient World, Ancient History Criticisms, Keith Hamilton and Ancient Architects. It doesn't take long to connect the dots and realize there was an advanced ancient global civilization and most of their existence has been lost.