Aliens Landed on Earth in the Past & Will Be Back Again?

It is a fact that the evolution of human civilization and greater learning currently remain a puzzle to humanity. Significantly much more proofs indicate that ancient civilizations had an incredible knowledge of Astronomy, Science and Mathematics that in several instances rivals the current civilizations. At the same time these old civilizations were expected to be a single step out of the Stone Age. These ancient civilizations created large structures that have stood the test of time and even with the current engineering and equipment would be difficult to replicate. How did they accomplish this? Why did they believe it was very crucial for future decades to observe their work? Exploring at ancient records from the Maya, Egyptians, Hopi Indians, Aztec and many other early people, they all bring up unusual phenomena that emerged from the sky similar to our contemporary time UFOs. Many of these ancient civilizations had philosophies in “gods” that interacted with or made them.