There is always a possibility for our world in our distant past to have been invaded by Aliens. I say a Possibility as we was not there for one and so much can be interpreted from ancient tablets, Rock Carvings.. ect, That seam to tell of the same story all over the world. A coincidence maybe? Surly it goes way beyond coincidence. After all we have seen a fraction of history in the same way and take that as a truth.
so should we do do the same with these, Even if it does go beyond our way of life as we know it.
If Aliens do exist, We don't know how powerful they really are and that if the past has been hidden or ridiculed to leave us in the dark. For that alone leaves me thinking some of it is possibility at least.
I would say though to anyone if this interests you. To do your own research and see what possibilities work for you :-)