Ancient monuments arrayed in accordance with the movement of the heavenly bodies. The story, written in stone, famous rulers of other worlds. Calendar, to accurately predict the displacement of the axis of the Earth every 26,000 years. Themselves to create the Maya in Central America, one of the most advanced civilizations of the ancient world? Or they have no other source of knowledge that is outside of our world?
They did not know of any metal or electricity, but had developed mythology, language, and religious culture. They knew better than any other astronomy of contemporary civilization. Maya felt the need to calculate the exact time as their gods had to go back. Millions of people around the world believe that in the past we were visiting extraterrestrial beings. What if it's true? Whether ancient aliens helped build our story? Who were they? Whence came they? What is left behind? Where did? Return it?
Watch Aliens in the past — Time Travelers