Science Channel HD

With winter looming, Clayton and Luke race to excavate two massive trike skulls, while the Harris-Bolan crew searches for a crucial missing femur for their rare ceratopsian; on the Abercrombie Ranch, Andre discovers a mother-lode of Ice Age bones.

Clayton gets news about the Nano sale and as a winter storm barrels in, he races to extract a rare trike tail; the Harris-Boland have finally found evidence of Ceratopsian skull; and on the Abercrombie ranch, Andre struggles to excavate a big tusk.

When a valuable fossil is trapped in a precarious location, Clayton brings in a team of horses and a helicopter to help extract it; Mike comes face to face with Cowboy Rex; Andre makes a difficult decision to save the Abercrombie mammoth.

Clayton Phipps makes a shocking discovery at the Trike site; the Harris-Bolan crew unearths what it believes might be an extremely rare ceratopsian; on the Abercrombie ranch, Andre Lujan digs up an enormous ice age mammoth tusk.

Clayton Phipps and his son Luke put it all on the line for a risky raptor fossil buried under 30 feet of earth. And the Harrises decide to go for broke to prep their multi-million dollar T. rex skull.

Clayton and Luke begin to excavate the deep overburden that covers the Tyrannosaurus rex site; while Mike Harris travels to Utah to prep the Cowboy Rex skull, Aaron, Jake and Tori think they're on a bucket-list discovery at the Duckbill site.

A NASA probe captures an image of a familiar structure on Mars' surface.

When the Soviet Union unveils its own space shuttle, the CIA hatches a secret revenge plot; recent discoveries shed new light on the destruction of Sodom and Gomorrah; a missing nuclear weapon could threaten a NASA base in the Arctic.

An astronomer records an unusual radio signal from beyond the solar system; FBI agents find classified documents at the home of a NASA scientist; when scientists discover strange DNA in the octopus, they examine if their origins could be alien.

The latest discoveries suggest life beyond this planet; scientists investigate if earth's life began elsewhere in the universe, and whether humans need to evolve to know for sure.

Cosmologists say there are black holes throughout the Universe, but they've never seen one, and it's almost impossible to study them directly.

Containing intricately carved concentric circles, the Towie Ball is one of the finest Neolithic stoneworks ever discovered; using cutting-edge imaging technology, experts investigate the purpose behind this 5,000-year-old black stone mystery.

The shattered skull of a 19th century railway worker is now one of the most astonishing objects in the history of medical science; experts explore this traumatic injury to reveal how it changed the field of neuroscience.

Investigating whether a gold death mask is the face of a king who fought in the Trojan Wars; three ancient chalk carvings could be the secret to constructing Stonehenge; how a printing plate from the UK Treasury ended up in an Austrian lake.

Investigating whether a machine can read personalities; an ancient golden mask painted with human blood; a cursed chicken pot.

A minuscule metal sphere containing two microscopic holes could be the smallest murder weapon in history; experts explore how this tiny object is linked to one of the most bizarre true crime cases of the 20th century.

A stone sphere, a hook and five fragments of wood are the only objects ever discovered inside the Great Pyramid of Giza; experts investigate if they can explain the mysteries behind the only surviving Wonder of the Ancient World.

In 1953, a team of archaeologists uncovers a bizarre, plastered human skull in the ancient city of Jericho; experts investigate the mysterious purpose and identity behind this 9,000-year-old clay-covered artifact.

Evidence suggests contact with interstellar travelers in the distant past may have influenced humankind and many of its sacred sites.

Using archival audio recordings, official transcripts and incident reports, UFO researchers investigate what really happened during encounters between law enforcement personnel and UFOs.

UFO experts investigate whether the value, reverence and desire for gold is the result of extraterrestrial landings in the ancient past.

An exploration into whether breakthroughs such as high-energy lasers, antigravity technology and super-advanced aircraft are the result of human efforts alone or contact with UFOs.

Although alien abduction claims are often dismissed as hoaxes or delusions, there are landmark cases that scholars struggle to refute; Calvin Parker retells his harrowing experience of being abducted near the Pascagoula River in Mississippi.

UFO sightings have been caught on film across the United States, yet the government continues to deny the existence of extraterrestrials; recent news of the Pentagon's secret UFO program may reveal evidence of what the military has known for decades.

An exploration into whether breakthroughs such as high-energy lasers, antigravity technology and super-advanced aircraft are the result of human efforts alone or contact with UFOs.