The idea of Aliens visiting earth has been around for many years. In November 2006, the pilot, several crew members and many people at the Chicago O'Hare Airport observed a flying disc which is believed to be proof of extraterrestrial or alien visitors. Proofs that we have had visitors from outside of our world come from historical sites found in Egypt, Easter Island, Mexico, Peru, Stonehenge in Wilkshire England, the Giant Pyramid in Egypt or the magnificent Machu Pichu in Peru in the Cusco Region. Also found in Peru are the Nazca Lines, engravings on the ground which consists of geometrical lines and animal drawings that go on for several miles. These engravings are so precise they must have been made with guidance from above, in some form of aircraft. In Mexico according to legend, where the Pyramid of the Sun can be found, it is believed aliens landed and here the gods touched the earth. These large shrines have steps on both sides allowing people or aliens to climb down from the top of these magnificent structures to ground level. These giant stones from our ancient cultures remain as proof of an alien influence. Other discoveries that offer further proof besides the ancient monuments are alien looking skulls that have been recovered. In China another remarkable finding: an unidentified metal, highly skilled fabricated sphere shaped metals which didn't come from earth.
It is very likely there is life on one of the billions of planets that are in the universe. Even here on earth in the oceans waters in the deepest and darkest areas life exists from the largest of the ocean creatures to the smallest microbial being, showing that life can be created in any environment. In looking at the billions of planets that make up the Milky Way it is possible that alien life exists on one or more of those unknown planets. With the unknown galaxies that are still undiscovered by the scientific world it is more than likely that there is alien life, and they could very possibly be much more advanced than we are, making it possible that they are able to travel and have visited our planet in the past, which makes it possible for them to be currently here or that a visit in the future is not unreasonable.
In 1961 Doctor Frank Drake while working in West Virginia at the National Radio Astronomy Observatory created what is known as "The Drake Equation" he logically and mathematically established a list of planets that could support intellectual existence. He built this equation based on the fact that there are billions of suns with orbiting planets and moons making it possible for life to exist in these galaxies just as life exists on earth. In the Milky Way alone there are ten thousand possible societies according to the Drake Equation.