Could the darkest recesses of our planet contain important information left by our ancient ancestors? And within Earth's mysterious caves, might we find evidence of otherworldly contact? Throughout human history, some caves have been considered sacred places for spiritual encounter and enlightenment, while others have been feared as true portals to purgatory. What happens in these subterranean spaces that has the power to influence religions around the globe? Could some of Earth's deepest caverns be secret conduits to supernatural realms? In Charma, India, archeologists recently discovered 10,000 year-old prehistoric artwork of what appears to be extraterrestrial beings. Could these paintings be a visual record of alien encounters in the distant past?

The Great Sphinx in Giza is the largest and most studied monolithic sculpture on Earth, yet it remains one of humanities greatest mysteries. This ancient monolith defies explanation, pre-dates our earliest known civilizations and may hide the secrets of our very origins. While mainstream archeology theorizes that the Sphinx was built around 2500 BC, geological evidence suggests it is much older. If this is true, then who--or what--created the Sphinx? Researchers are now proposing the existence of a second, twin Sphinx on the Giza Plateau. If so, has it been deliberately hidden from mankind? The face of the Sphinx is believed to represent Egyptian pharaoh Khafra, yet the size and proportion of the massive carving suggests the head has been altered. Could the statue have originally represented an otherworldly being that came to Earth some 10,000 years ago, as Ancient Astronaut theorists propose?

There are those who believe that the evolution of technology is not entirely of our own making. Ancient Astronaut theorists contend that it is by extraterrestrial design that we have become so technologically interconnected--and that we are being watched by beings from beyond our world. Do stories from the ancient past hold evidence of alien overseers? The Book of Enoch describes divine entities called the Watchers descending to Earth to monitor humankind and aid in our advancement. Inca legend states that the god Viracocha created humans and taught them astronomy, agriculture and other advanced arts. The Maya civilization believed their supreme god Kukulkan taught humans writing, mathematics and science. In ancient Chinese legend, the divine ruler Huang Di introduced numerous advancements such as the wheel, weaving and writing. Could it be that our increased reliance on computers, cell phones, tablets, and the Internet is the product of extraterrestrial design?

Throughout history, many of the world's greatest thinkers have helped push civilization forward with their profound insights and extraordinary abilities. But the majority of these master minds say their brilliance comes from a place they don't understand--and arrives at times they're not expecting it. In antiquity, people in nearly every culture around the world believed they did not possess genius, but that genius possessed them, like a spirit. Could it be that the forces of inspiration that the ancients attributed to the gods really did emanate from an otherworldly source, as Ancient Astronaut theorists suggest? Whether it's Albert Einstein's theory of relativity, Edison's light bulb, or Russian chemist Dmitri Mendeleyev's Periodic Table of Elements, geniuses routinely say their best ideas come from dreams, visions, or hallucinated voices. Is it possible that genius is more than just the product of good genetics?

For thousands of years, in cultures throughout the world, people have practiced elaborate techniques to preserve the human body after death. The ancient Egyptians believed mummification ensured entrance into the next life. Buddhist monks in Japan practiced a shocking self-mummification process that began before death in the hopes of becoming a "living Buddha." And the Incas consulted the mummified remains of their kings to discuss affairs of state and the future. Ancient Astronaut theorists believe the global practice of mummification is not a coincidence, but proof that highly advanced extraterrestrials visited Earth in the distant past. Could our ancestors have witnessed a form of biological hibernation and then mimicked it with mummification? Could mummification have been an attempt to recreate suspended animation so often connected to extraterrestrial space travel? Or could the intention have been to preserve the body for future DNA removal?

Throughout history, incredible stories have been told of the dead rising from their graves, mummies journeying into the afterlife, and people on the brink of death mingling with deceased relatives in a celestial netherworld. Are they simply legends--or could some of these stories actually be true? From Jesus and Elijah to mummies and zombies, our culture is filled with accounts of beings who are able to lift the veil between life and death. And even today, scientists are trying to mimic this by suspending death in the operating room for hours at a time. Haitian priests continue the ancient practice of raising "zombies" from the grave. And microscopic organisms have been found that can resuscitate themselves after lying dormant for weeks. Are we on the verge of decoding the mysteries of life, death, and resurrection?

Messages embedded in sacred religious texts, as well as in the design and location of ancient monuments that may reveal the purpose behind human existence.

It is a story told in more than twelve hundred cultures around the world--the gods sent a great flood to wipe out humanity for its disobedient and wicked ways. Do these numerous creation myths point to an actual deluge, one that engulfed the world and spared only a chosen few? New evidence suggests that many fabled aspects of these flood myths may, in fact, be true. From traces of a major meteor impact in the Indian Ocean, to a worldwide ash layer, and even remnants of Noah's gravesite, scientists are starting to put the pieces of a very deadly puzzle together--a puzzle that some believe was created by extraterrestrial beings. Did humanity narrowly escape extinction? And are the ancient stories correct--that alien beings are the reason we survived? Ancient Astronaut Theorists believe they are--and that celestial beings are poised to save us again when another catastrophe sweeps across the Earth.

The Civil War nearly destroyed the great experiment known as the United States of America, but is it possible that the preservation of the republic was influenced by extraterrestrial beings? Abraham Lincoln described strange visions and premonitions that occur before pivotal moments in his presidency. Union officer Ambrose Bierce wrote about mysterious disappearances and inter-dimensional travel. And a ghostly image of George Washington was witnessed by hundreds of soldiers at Gettysburg–prompting an official government investigation. Is it possible that extraterrestrials were present during the Civil War? If so, were they simply passive observers, waiting to see if our fragile democracy could survive this test? Or did they take an active roll in order to preserve the Union?

With infrared satellite technology detecting pyramids hidden underneath the sand in Egypt and airborne laser sensors discovering long lost pyramids beneath the jungles of Central America, many believe we have entered a new pyramid era--an age of discovery that will be marked by unimaginable new findings. 21st century excavations are also revealing fascinating new facts about pyramids that could potentially rewrite history. Archaeologists now believe the ancient pyramids in Peru are older than the Egyptian pyramids, and a recently surveyed megalithic site in Indonesia is now suspected to be a step pyramid built by a long lost civilization 20,000 years ago. But what can explain ancient man's apparent obsession with building pyramids? Ancient Astronaut theorists believe the world pyramid phenomena is not a coincidence, but evidence that Earth's earliest inhabitants may have had help from extraterrestrials.

Many of humanity's most significant turning points have bore witness to unexplainable events. Is this merely coincidence, or could it be evidence that the course of human history is being manipulated by an alien agenda? Ancient Astronaut theorists have long proposed that extraterrestrials played a pivotal role in our past, and some believe they continue to keep a careful watch over the progress of mankind. Even high-level government officials have made claims that extraterrestrials are visiting our planet with an interest in our technological advancements, including former Canadian Defense Minister Paul Hellyer, who stated that that the cosmos are teaming with life. Could the UFO phenomenon be real? Have extraterrestrials been monitoring human progress for thousands of years--at times helping us to advance, and at other times holding us back?