Giorgio Tsoukalos looks at mysterious teachers who have appeared throughout history, including a biblical patriarch, a race of fish-people, and Egypt's most controversial Pharoah...

For more than a decade, Ancient Aliens has collected dozens of reports of encounters with strange and mysterious beasts. Now, Ancient Astronaut Theorist Giorgio Tsoukalos takes a look back at The Top Ten Extraordinary Creatures we've investigated-creatures that just might provide compelling evidence of extraterrestrial visitation...

Counting down the top 10 locations around the world that may be hiding alien bases, including a cavern beneath the ice of Antarctica, a lake in China that is a hotspot for UFOs, and a pyramid under the slopes of Mount Denali...

Ancient Aliens is counting down the top ten scariest encounters that just might be evidence of extraterrestrial visitation. From an encounter in rural Texas that left onlookers with unexplainable injuries, to mysterious cattle mutilations, and a man who was abducted in front of a group of people. Are these frightening encounters proof of extraterrestrial contact?

Ancient Aliens is counting down ten of the most intriguing-and mysterious-symbols and codes found across the globe that just might contain proof of otherworldly contact. From glyphs in the Peruvian desert, to spiral petroglyphs embedded with advanced math, and a language with an otherworldly origin, could these codes unlock the secrets of our extraterrestrial past?

Ancient Aliens is counting down the top ten most devastating disasters ever documented that might have an otherworldly connection, from a flying monster at a nuclear incident, a meteor that wiped out the dinosaurs, and a deadly virus that might be from another world. Could these disasters be proof of extraterrestrial contact?

More than 7,000 years ago, the ancient Sumerians established what is considered the world's first civilization, and they credited their extraordinary achievements to their gods, the Anunnaki. But is it possible that these powerful beings were, in fact, extraterrestrial visitors to Earth?

Along the Earth's north 37th parallel there have been so many reports of unidentified flying objects, animal mutilations, and other mysterious events that it has been dubbed The UFO Superhighway. Could there be something about this latitude that is attracting extraterrestrial visitors?

For thousands of years, Scotland has been an epicenter of otherworldly phenomena; it is home to mysterious ancient stone circles, stories of strange beings, and is a major hotspot for UFO sightings.

Throughout the world there are mysterious ancient stones shaped into perfect spheres; many of them show clear evidence of being man made and some completely defy explanation; the mystery of the stone spheres could provide clues about humankind's past.

Considered by many to be the greatest civilization in the history of the Americas, the Maya thrived for more than 2,000 years. Now, new evidence is being discovered that completely upends our understanding of this ancient culture... and might provide evidence that the Maya came in contact with extraterrestrial visitors.

For thousands of years, cultures around the world have held a belief in stargates through which beings have traveled to Earth from distant points in the universe and even other dimensions. Could such portals truly exist? And if we obtain the key to unlocking the stargates, will we find a cosmos teaming with life?

For decades, incredible claims have been made about an extraterrestrial presence on Earth, and the government has gone to great lengths to discredit them.

For thousands of years, humankind has attempted to make contact with beings from beyond Earth; now, the search for extraterrestrial intelligence is ramping up, with new technologies allowing individuals to explore the universe.

Dr. Jacques Vallée holds multiple scientific degrees, is a best-selling author, and is one of the fathers of the internet. But he is best known for his revolutionary work in the field of UFOs, and his bold theories challenge our notions of alien life. Will Dr. Vallée's incredible work soon lead to answers about what has been happening in our skies for thousands of years?

Throughout ancient cultures there are stories of god-like beings providing instruction to early humans, helping our ancestors to establish the first civilizations and teaching them in various disciplines. Could it be true? And do mysterious figures who appear throughout history provide evidence that these otherworldly teachers have been with us all along?

Deep beneath the sands of Egypt lie 24 enormous sarcophagi - and every one of them is empty. What purpose might these giant tombs have served? And is it possible that the perfectly carved stone boxes - each weighing more than 70 tons - were designed not by humans... but by otherworldly visitors?

For more than four decades, award-winning journalist Linda Moulton Howe has covered the most mysterious phenomena on Earth. Could her investigations on everything from bizarre animal passings to crop formations and alien abductions lead us to a profound new reality?

From biblical patriarchs to modern day alien abductees, throughout history, there have been people who claimed to have contact with otherworldly beings. And often bearing important messages for humanity. Could it be that they have been chosen to help carry out an extraterrestrial agenda?

Puma Punku in Bolivia features some of the largest stone blocks on Earth, each carved with incredible precision. But the blocks lie scattered across the landscape, baffling archaeologists as to what the ancient site might have been. Could new advancements in technology help to solve a centuries old puzzle-and offer proof of alien intervention on Earth?