Earth is estimated to be 4-5 billion years old.

Human civilization evolved over 4-5 million years.

That means we could have potentially had 1000 different civilizations evolve from nothing to our current level of humanity during the life of this planet.

I personally believe that at least one very advanced civilization existed in the past and evolved to the point that they had fairly advanced technological capabilities. This would help account for many unexplained archeological mysteries, possibly even an ancient satellite.

Or I'm completely full of crap and it's from.....