Ancient Aliens is counting down the world's top ten alien cover-ups, from the famous Roswell Incident to a secret military base rumored to be housing ET technology to recently released UFO videos captured by cameras on Navy fighter jets. Has there been a massive cover-up regarding the truth about an extraterrestrial presence on Earth?

Scientists now know that seven human-like species lived alongside Homo sapiens for thousands of years. But why is it that only humans survived? Is it possible that we were the product of extraterrestrial experimentation? Ancient Astronaut theorists Giorgio A. Tsoukalos, David Childress and William Henry will be joined by Rabbi Ariel bar Tzadok and filmmaker Caroline Cory to investigate the mystery of the Human genome, in an attempt to determine if human beings are the product of an extraterrestrial experiment. Might the ultimate proof we are not alone in the universe be hidden in our own genetic code?