[The Louiswu]

Wouldn’t surprise me one iota if there were any number of civilizations on this Earth before we came along.

[Angelino97]

H.P. Lovecraft based many of his stories on that premise.

[notdownwidems]

who is we? if you mean Homo sapiens and we define civilizations broadly enough, maybe, an interesting theory, thus far unproven, but with some tantalizing clues, ie the geographical clues, homogeneity in folklore about the flood across continents, legend of Atlantis, etc.