[EscaCsamas]

I am not sure what you mean by powerful civilisations but if there have been some advanced civilisations on Earth before (which I believe there have been), they would have been aware of the Universal Laws and consequences of such behaviours led by greed, etc.. Maybe they have made a choice to move on somewhere else, in different reality, like Mayans might have done..

I have always thought that there is much more than we could ever know on this planet, I really don't think that on this plane we'll ever be able to access the Ultimate Truth, although who know what the Ultimate Truth is, only Creation do/does.. Maybe just being able of knowing True Love is enough, maybe facts don't matter as long as we come to know Love..