Legends from around the world speak of sacred entryways to the land of the gods. Gates that allowed instant passage not just beyond the confines of Earth, but beyond space and time. Are such passages--or stargates--just inventions of myth, or might this kind of interstellar travel have existed in the ancient world? In Turkey, researchers uncover a mysterious and toxic cave that the ancient Greeks described as a physical gateway to Hell. The Incas believed their empire began when divine beings stepped through portals in a mountain. In Northern Mexico, legends describe strange, otherworldly creatures appearing and disappearing within the remote ruins of an ancient civilization. As science continues its quest to create technology that would allow humans to travel to the stars, is it possible that these celestial pathways already exist?

Strange rock carvings from 8,000 B.C. Unexplained sightings in the new world. And a frightening anomaly plaguing the American West. Is there more to America's past than is found in our history books? Could the mysterious stories and relics found throughout the United States be evidence of extraterrestrial contact in the distant past? In 1909, the Phoenix Gazette reported the finding of a strange man-made cave filled with ancient objects and mummies. Could there be a connection between the mysterious cave and the legend of Native American ancestors called "Star Beings?" Strange lights and unexplained weather anomalies were documented throughout colonial America. Is there evidence that early American settlers had close encounters with extraterrestrial entities? Could UFO sightings and reports of alien contact be part of America's untold history?

On every continent, there are stories of children who "stand out" for their strange abilities and advanced knowledge. They are said to have knowledge of things they shouldn't or couldn't know. The ancient Greeks, Egyptians and many other cultures have legends about exceptional children who are the offspring of humans and the gods. Could the stories be more than mere myth? Is it possible there are children being born on Earth today who can access their alien DNA--a connection that endows them with special gifts and the power to transform society?

Sealed vaults possessing a strange and deadly curse, mysterious relics believed to be under otherworldly protection, and riches so priceless, it has cost men their lives. On every continent there are stories of incredible treasures that have been lost for centuries. Is it possible that the world's greatest ancient relics are hidden on purpose--and protected by an extraterrestrial source?

Throughout human history, the planet Mars has captured our imagination. Ancient Egyptian astronomers were the first to record the red planet on a chart of the cosmos known as the Senenmut star map. Scholars believe Mars played an important role in Maya astrology that's described in the Dresden Codex. And modern translation of Sumerian and Babylonian origin myths record a cataclysmic event occurring on Mars. Is our fascination with Mars simply because of its striking red color and prominence in the night sky? Or might we have a more profound extraterrestrial connection? For nearly 40 years, probes have been sending information about Mars back to scientists here on Earth. Photographs of the mysterious planet reveal mountain-like formations known as Twin Peaks and a strange, humanoid face carved into Martian rock. Has NASA found definitive signs of life on Mars that they're intentionally keeping from the public?

Throughout history, spiritual leaders known as shamans have healed, protected and advised their people. But are they simply putting on elaborate ceremonies? Or could they be in contact with extraterrestrial realms? The Mongol army crushed their enemies and built a massive empire with the help of powerful shamans who could manipulate the weather. Amazonian shamans believe otherworldly beings taught them how to create a powerful brew that allows them to travel beyond Earth to gain knowledge. And on the desert plains of the Kalahari, the San Bushmen practice elaborate trance dances that unlock supernatural capabilities in their healers. Can shamans really communicate with otherworldly beings? Is it possible that through these spiritual mediators, extraterrestrials were able to influence mankind in the distant past? And could such celestial communication continue even today?

Earth is home to 10 quintillion insects. In cultures throughout the world, insects have been honored, feared and even revered as gods. But might these strange creatures that have inhabited Earth for hundreds of millions of years provide a link to extraterrestrial beings? Is it possible the ancient Egyptians encountered alien beings that had an insect-like appearance? Are the scorpion-tailed locust described in the Book of Revelations some type of advanced weaponry wielded by an extraterrestrial being? Might the Ant People that appear in both Greek and Native American mythology really be grey aliens? Is it possible that there is a connection between insects and aliens? Are insects related to beings from beyond our world, as some Ancient Astronaut theorists suggest? And if so, might they have a secret purpose we have yet to discover?

Demonic seduction... hybrid offspring... and strange abductions. In cultures throughout the world, there are tales of intimate encounters with otherworldly beings. But could these stories be more than just mythology? Scientific deconstruction of human genetic makeup has revealed that our origins are not what we once believed. Biologists have determined that early humans mated with several other species of intelligent hominids. Neanderthals, Denisovans, and a third--as of yet unidentified--species may also be represented in our DNA. Is it possible that tales spanning from fallen angels to Greek gods, medieval incubus and succubus to today's extraterrestrial sexual encounters are all one in the same? And if so, is it all part of a greater agenda? Might examining these experiences provide not only evidence of extraterrestrial sexual intervention in the remote past, but also reveal the true nature of mankind's origins?