The Earth is a relatively young planet. It has been visited by the Galactic Humans over a million years ago, even during the time of the dinosaurs. Our evolution involved not only natural evolution based on random mutations and natural selection but also involved upgrades by spiritual and alien genetic engineers. Among spiritual beings involved in our evolution, an important role was played by angelics, elementals and other spirits. Thus, our evolution was shaped by three parallel processes: natural evolution, targeted evolution directed by the spirits and intelligent manipulation by extraterrestrials.
Prehistoric man on Earth developed very slowly. For a very long time, the prehistoric man was using only very simple tools and didn't change the tools and didn't evolve for several hundred thousands years. At the same time, the Earth was a refuge to some of the alien races.
The Lemurian civilization existed on Earth likely over 0.5 million years ago. We might not have the archaeological traces of the Lemurian civilization because it was in a higher density. The Lemurians were more advanced than prehistoric man or modern humans. Then the Atlantean civilization was formed, with its highly developed technologies, cities and a large population. Both Lemurian and Atlantean civilizations were openly visited by extraterrestrials. The Earth's climate was artificially controlled using a grid of temples and artificial satellites. The Atlantean civilization misused genetic engineering and dark magic. They misused the advanced technologies for military purposes, and as a result they went through a series of wars and other catastrophes. The last and biggest catastrophe that destroyed Atlantis and Lemuria was about 23,000 years ago. The enlightened population of Atlantis escaped from the surface of the planet before the catastrophe and settled in Pleiades, the Andromeda galaxy and in inner-Earth cities. The surface civilization lost its culture and population, while the remaining humans continued developing our civilization from a very basic level.