Mysterious places can be found around the Earth, and, inexplicably, UFOs are often sited near these mystical areas. Planes and ships unaccountably disappear in the infamous Bermuda Triangle. Strange magnetic anomalies in Mexico's Zone of Silence have not only drawn missiles off their course, but seem to pull meteorites out of the sky. An ancient doorway carved into a sheer rock wall in Peru's Puerta de Hayu Marka is said to be a portal to other worlds. Markawasi's plateau is filled with strange rock formations allegedly left behind by an ancient advanced civilization. What connections do these and other "hot spots" share? Is it possible that ancient extraterrestrials also knew about these mysterious places?

Myths and legends have long been regarded as fantastic stories that describe powerful gods, mutant giants and fearsome monsters. But why do so many different cultures, separated by vast distances, tell the same stories? Is it possible that myths and legends were really eyewitness accounts of ancient astronauts descending to Earth? Ancient texts are filled with stories of gods interacting with humans, offering wisdom, technology, and even impregnating women. Could the demigods of mythology have been the offspring of alien and human unions? If so, could aliens have supplied the Missing Link that accelerated human evolution, advancing our civilization and making us who we are today?

Ancient underwater cities can be found around the globe, but could these aquatic worlds be the ruins of unknown civilizations--or even proof of extraterrestrial visitations? The infamous tale of the long lost city of Atlantis may be a preserved memory of an ancient alien metropolis. Beneath Lake Titicaca in Peru, the ruins of recently discovered temples support local legends of an underwater UFO base. Ancient Indian texts, known as Sangams, describe sunken cities where aliens and humans intermingled thousands of years ago. Who could have built the 600-foot stepped stone structure off the coast of Japan--a site that may predate the Egyptian pyramids by thousands of years? Could evidence of ancient alien contact lie buried in Earth's deepest oceans?

If extraterrestrials influenced human history, can evidence of their existence be found in hidden tunnels and caverns around the world? Could a cave in Ecuador contain metallic books inscribed with secrets of alien technology? Was an ancient underground city in Turkey built with alien help... or as a refuge from an alien attack? Rumors of the U.S. military working alongside aliens in a secret base inside a mesa in New Mexico continue to swirl, Native American legends mention strange inner-Earth beings, and recent archaeological discoveries in the Yucatan may point to an extraterrestrial reality behind.

If ancient aliens visited Earth in the remote past, could they have given us advanced technology, past down through human history? And could this technology have helped the Third Reich build mysterious weapons and crafts far beyond the limits of 20th century science? During World War II, there were reports that the Germans built an operational flying saucer, known as the Hanebu, which was said to use mythical technology found in ancient Indian texts. Another craft was rumored to have been constructed with the help of psychics and mediums who claimed to have received detailed blueprints from extraterrestrial beings. Is it possible Hitler's quest for world domination was aided and abetted by ancient extraterrestrial technology that was rediscovered? And could the allegedly rebuilt alien devices developed in Germany have played a role in America's ability to land a man on the moon?

Super-heated death rays... High-tech rockets... Powerful sonic weapons... Are these examples of modern day science or could these technologies have originated thousands of years ago? Is it possible that early man possessed scientific knowledge far beyond that of our own century? Ancient texts, folklore and art suggest humans witnessed disc-shaped flying machines and fire-spewing chariots. Could these be accounts of flying saucers and rocket ships? And if so, was advanced technology left here by visitors from the stars? Did mankind's quest to unlock the secrets of levitation, anti-gravity and laser technology merely spring from our imaginations or did these ideas come from otherworldly beings?

Biblical texts and ancient lore frequently describe winged creatures carrying messages from the heavens. But are angels merely the product of mankind's imagination--or do they really exist? If so, where do they come from? Ancient astronaut theorists suggest that the Bible's Old Testament reads like a handbook on extraterrestrial visitations. Accounts of angels can also be found in Islamic and Indian texts. Infinite stories around the globe describe unearthly guardians, entrusted to both observe and protect as well as tales of powerful warriors bringing about everything from plague to peace. Are angels really supernatural beings from heaven, or something more? If so, might angels really be travelers--visiting Earth from distant planets?

If ancient aliens visited Earth, can evidence of their existence be found in the mysterious structures that still stand throughout the world? Inexplicably, megalithic structures found on different continents are strikingly similar, and the cutting and moving of the massive stones used to build these magnificent feats would be a struggle for modern day machinery, let alone ancient man. Ancient astronaut theorists suggest that the standing stones in Carnac, France were used as an ancient GPS system for ancient flying machines. The recently discovered Gobekli Tepe in Turkey, which has been dated back 12,000 years, has finely chiseled pillars that experts describe as a Noah's Ark in stone. Is it possible that extraterrestrials assisted primitive man in constructing these unexplained structures? If so, what was the purpose of these grand projects?

If ancient aliens visited Earth, were they responsible for catastrophes, wars and other deadly disasters to control the fate of the human race? The story of the Great Flood sent by deities to destroy civilizations exists in many prehistoric cultures. There are ancient descriptions of extraterrestrial battles that caused wide-scale destruction, and even reports of UFOs lurking in the shadows of recent natural disasters. The Book of Revelations and the Dead Sea Scrolls describe a future apocalyptic battle between good and evil that will destroy our world. Are these ancient texts proof that aliens are hostile and planning a violent return? Or might they be our saviors, ensuring our survival as a species during times of devastation?

Unearthly visitations... Heavenly messengers... Close encounters... Accounts of humans interacting with celestial beings have existed since the beginning of mankind. Many of these encounters resulted in moral, philosophical and artistic inspirations. But did these contacts involve ethereal beings from heaven or extraterrestrials from other worlds? Are holy books the word of God, or guidebooks passed down by more advanced civilizations? Who told Joan of Arc how to defeat the English Army--saints or extraterrestrials? Could a young boy from India have learned advanced mathematical formulas from a Hindu goddess? What message did an American serviceman receive while touching an alien aircraft? If the Ancient astronaut theory is correct, then are beings from other worlds communicating with us for our benefit... or theirs? Just what is the purpose of these alien contacts?