The History Channel

NASA has been exploring space for decades, and there are persistent reports that the agency has uncovered surprising information about UFOs. The team speaks with former astronauts, employees and engineers, and delves into NASA videos to see if the space agency knows more than it is letting on.

Angkor Wat, Cambodia, is the world's largest ancient religious temple. Within its megalithic ruins, researches have discovered a depiction of a species of dinosaur--a stegosaurus. But how could the ancients have had knowledge of animals that mainstream science says died out millions of years ago? Why are dinosaurs extinct? Did an alien race of beings kill off the dinosaurs to make room for humankind?

At nearly 14,000 years old, the ruins of Puma Punku are the oldest and most baffling on the face of the Earth. No one knows who designed and built this complex of sophisticated inter-locking blocks, and then vanished. Researchers investigate the ruins on-location in Peru and present new computer analyses. Forensic evidence on the ground, together with local myths and legends, suggest this site may have been designed and even once inhabited by a species of extraterrestrials.

In 1975, Travis Walton claims to have been abducted and taken aboard a space ship inhabited by extraterrestrial beings. Several people witnessed his encounter and nearly 40 years later Walton's story of alien abduction, missing time and mind-telepathy manipulation has not wavered. But researchers say that abductions are not a modern phenomenon. The Hebrew Bible is filled with stories of abductions by otherworldly beings. Jonah, Moses, Ezekiel and Enoch all depict what can best be described as physically being taken to other dimensions and then returned. Is it possible that extraterrestrial beings have been abducting humans for thousands of years and if so, might there be an alien agenda behind the phenomena?

On October 26, 1994, the U.S. government made their first official acknowledgement of Area 51. Six months later, nearly 4,000 acres of previously public land surrounding the base were closed. Now, over a decade later, satellite photos reveal new buildings, towers and runways finishing construction. Secret flights with blacked-out windows bring passengers from Las Vegas. And security surrounding the perimeter of the base is tighter than ever. The team heads to the epicenter of UFO and military conspiracy theories to visit new vantage points, speak with former base employees, and search the skies above America's most top-secret facility.

NASA has been exploring space for decades, and there are persistent reports that the agency has uncovered surprising information about UFOs. The team speaks with former astronauts, employees and engineers, and delves into NASA videos to see if the space agency knows more than it is letting on.

Mining is one of the oldest endeavors of man. See where modern ore processing machines go when they wear out. Will they be restored, or scrapped for the furnace. Incredibly, a former uranium mine is now a world-famous health spa. A giant smelting facility has been transformed into a world class golf course. In one of the most extensive and complex projects of its kind ever attempted, witness the dramatic transformation of a 110-square mile mining complex.

A great ship that has reached the end of its useful life is often destroyed in weapons testing or cut up for scrap. Watch a salvage operation that saves battleships sunk during Pearl Harbor. Discover a historic ship Boneyard that is literally the foundation of a city and ships that are purposely sunk to become living reefs. Some of the fastest boats on the water have been hot-rodded from the engines of aircraft of three wars. Follow the dismantling of these large structures and learn of their unusual after-life.

For years, people have claimed to have had direct, personal contact with an alien. In this episode of our series, the team tracks down several people who claim to have had such contact. They'll also work along side medical and scientific professionals to try and discover what, if anything, really happed to these people.

For years, the team has been tracking an elusive prey only seen at night--ships, shaped like triangles, impossibly huge, and videotaped over cities around the world. But are they ours, or theirs? The team investigates numerous UFO sightings that have recently been reported in Sonora, California, a charming old West town nestled in the Sierra Nevada Mountain Range nicknamed Triangle Alley. What makes these sightings so compelling are rare daytime footage of triangles in flight. This footage will be digitally analyzed to determine if these are indeed UFOs and not military jets. The team will also visit Texas to speak to military experts and witnesses to compelling triangle sightings. It's speculated that these triangle craft have been visiting us for centuries.

The Alaska Ocean is the largest factory-fishing boat in the US fleet. The crew's mission: hunt down, catch and process 300 tons of Alaskan Pollock each day on the unforgiving waters of the Bering Sea. We travel with them on the last voyage of a long and grueling season. The crew reveals the inner workings of one of the most sophisticated and complex vessels afloat. It is half fishing boat, half floating factory, processing and flash freezing Alaskan Pollock as fast as its crew can catch it. To meet their seasonal quota of Pollock, the crew must overcome obstacles of weather, mechanical dangers aboard the sea-tossed ship and the wiliness of the fish themselves. Captain Scott Symonds takes us inside the amazing ultra-modern world of high stakes commercial fishing where a wrong decision on his part can cost not just the season's catch, but also the lives of his crew.

Our 49th state is one tough terrain. In the air, on the ground--and deep beneath it--survival here requires an amazing array of technological innovations. From buildings to highways, brutal winters to bug-infested summers, this unforgiving landscape demands creative work-arounds. And then there's the constant threat of natural disasters...tsunami, anyone?

It's the most popular fish in the American diet. From the school lunch box--to the high end sushi bar--to the outdoor barbecue, tuna crosses all demographic lines. We'll go fishing with the men who risk their lives to bring in a haul, stop in at Bumble Bee, the only major tuna cannery still operating in America, and visit the world's largest fish market in Tokyo, where a single tuna can sell for as much as $100,000. We'll also explore worldwide efforts to save the giant bluefin tuna, which has been over-fished to a point of peril. Then we'll head to sea with scientists who track the tunas' inter-oceanic migrations, and travel to South Australia, where entrepreneurs seek to breed the mighty bluefin in captivity.

The US has become the culture of BIG--just look at the importance of size and how it has been infused into the lifestyle we choose to live, whether it's our homes, our appliances such as large screen TVs or even eccentric stretch limos. But big has also affected what we eat. This episode explores America's growing obsession with plus-sized meals and how we cook them! Discover the largest everyday offerings of gargantuan portions--from the biggest stacked burger in the world (at almost 250 pounds), a plus-sized Sicilian pizza that feeds almost 75 people, a 72-ounce steak no real cowboy can resist, and the seven-pound hot dog that's too big for a bun. Top it all off with a giant cupcake, humongous cinnamon roll or a five pound gummy bear... and chase it down with a monster bottle of beer that holds over 101 ounces of brew.

Journey through a netherworld of ancient passageways and secret chambers that reveal as much about life as they do about death. On this mystical trip into the mysterious world of death, we visit hidden tombs that reveal lost civilizations and buried treasures, and ancient underground cemeteries that became refuge for the oppressed.

Informational programming.

Informational programming.

Informational programming.

Informational programming.

Joseph "Bunco" Kelly was the kingpin of the secret Shanghai Underground--numerous, solidly constructed brick and stone tunnels and secret chambers that snaked their way beneath the streets and buildings of Portland, Oregon. The system allowed Kelly's corrupt operation to run smoothly. Kelly's gang was not averse to "creative" business deals, using the tunnels to deliver a cigar-store Indian to one ship captain and a number of corpses to another while representing them as able-bodied workers!

Mining is one of the oldest endeavors of man. See where modern ore processing machines go when they wear out. Will they be restored, or scrapped for the furnace. Incredibly, a former uranium mine is now a world-famous health spa. A giant smelting facility has been transformed into a world class golf course. In one of the most extensive and complex projects of its kind ever attempted, witness the dramatic transformation of a 110-square mile mining complex.

A great ship that has reached the end of its useful life is often destroyed in weapons testing or cut up for scrap. Watch a salvage operation that saves battleships sunk during Pearl Harbor. Discover a historic ship Boneyard that is literally the foundation of a city and ships that are purposely sunk to become living reefs. Some of the fastest boats on the water have been hot-rodded from the engines of aircraft of three wars. Follow the dismantling of these large structures and learn of their unusual after-life.

For years, people have claimed to have had direct, personal contact with an alien. In this episode of our series, the team tracks down several people who claim to have had such contact. They'll also work along side medical and scientific professionals to try and discover what, if anything, really happed to these people.