Science HDTV (SCIHD)

A former CIA operative investigates new evidence of a top-secret group known as the Nightstalkers, a clandestine team of the world's best aviators involved in the assassination of Osama Bin Laden and other dangerous black ops. (Repeat).

Newly declassified documents reveal that the US Space Force is the culmination of decades of top-secret military programs to weaponize the cosmos. Special access exposes the cutting-edge weapons and sci-fi defense systems behind real-life star wars. (Repeat).

An ancient piece of corroded metal is more than it seems: an alien-looking device of intricate dials and cogs. Using cutting-edge imaging technology, experts examine what could actually be a 2000-year-old computer. (Repeat).

Experts examine an ancient tablet could be the key to a lost civilization. (Repeat).

A startling gold death mask could be the face of a king who fought in the Trojan Wars. Then, three ancient chalk carvings could be the secret to constructing Stonehenge, and how a printing plate from the UK Treasury ended up at the bottom of an Austrian lake. (Repeat).

Looking into the possibility of a machine being able to read personalities; a golden mask from the past, painted with human blood; a cursed chicken pot. (Repeat).

When a mysterious fog and a huge explosion strike at once, some suspect a napalm attack, but using cutting-edge tech, experts find that the truth could be more dangerous than ever imagined. (Repeat).

Using cutting-edge science, experts investigate a nightmarish phenomenon caught on camera, as eyewitnesses fear an alien invasion. (Repeat).

When footage of a strange deep-sea vessel is uncovered, experts wonder if its evidence of an autonomous alien craft sent to explore earth, and using cutting-edge tech, investigators follow the clues to an unexpected explanation. (Repeat).

When something strange is recorded flying in Mexico, some wonder if it's a witch reputed to kidnap children, while others believe it's evidence of a new way to smuggle drugs or a top-secret technology; the latest science helps experts investigate the truth. (Repeat).

On a Native American reservation in Utah, evidence of a man transforming into an animal is caught on camera, and some experts ask if it's proof of a Skinwalker, a legendary evil creature that can shapeshift into a deadly beast. (Repeat).

Experts look into the volcano underneath New York City. (Repeat).

When something strange is recorded flying in Mexico, some wonder if it's a witch reputed to kidnap children, while others believe it's evidence of a new way to smuggle drugs or a top-secret technology; the latest science helps experts investigate the truth. (Repeat).

On a Native American reservation in Utah, evidence of a man transforming into an animal is caught on camera, and some experts ask if it's proof of a Skinwalker, a legendary evil creature that can shapeshift into a deadly beast. (Repeat).

Experts look into the volcano underneath New York City. (Repeat).

When footage of a strange deep-sea vessel is uncovered, experts wonder if its evidence of an autonomous alien craft sent to explore earth, and using cutting-edge tech, investigators follow the clues to an unexpected explanation. (Repeat).

A startling gold death mask could be the face of a king who fought in the Trojan Wars. Then, three ancient chalk carvings could be the secret to constructing Stonehenge, and how a printing plate from the UK Treasury ended up at the bottom of an Austrian lake. (Repeat).

Looking into the possibility of a machine being able to read personalities; a golden mask from the past, painted with human blood; a cursed chicken pot. (Repeat).

A glass-breaking gorilla and a speed-racing sea lion face off against a snowman in the desert and an underwater wheelchair. (Repeat).

A Gemini 8 incident in which an unexplained spin threatened the crew; an Apollo 17 photo that seems to show a U.S. military outpost on the moon; and whether the oceans of Jupiter's moons hold life. (Repeat).

A dark spot on the sun; an unusual spacecraft; UFOs. (Repeat).

White dwarfs are small dead stars that are capable of exploding into supernovas and destroying planets. (Repeat).

The search is on to locate which star could be next to explode into a supernova, a stellar detonation powerful enough to destroy all life on Earth. (Repeat).

A special drone uses cutting-edge technology to fly deep into treacherous, hard-to-reach mountains on dangerous search and rescue missions. A hi-tech ice machine works tirelessly at a Toronto airport to keep flights running in brutal conditions. (Repeat).

The world's only actual all-terrain vehicle is an Arctic mega monster that can conquer land, snow, and water in dangerous conditions; elsewhere in avalanche country, only one machine can climb deadly mountains and protect a major highway. (Repeat).

As melting ice threatens a town, an amphibious mega-machine battles the elements to save the day; in the Arctic, the Canadian Air Force relies on a massive transport aircraft to deliver supplies and personnel to far-off places. (Repeat).

How tourists explore the far reaches of northern Canada and gain exclusive access to polar bears on custom-built rovers. Also, how the Twin Otter aircraft drops much-needed supplies to isolated villages. (Repeat).

A team of experts uses an engineering marvel to access a perilous place covered in the snow. (Repeat).

Search and rescue operations in arctic conditions rely on a special helicopter. (Repeat).

A helicopter tailor-made for extreme environments aids US Army rescue efforts in some of the harshest conditions, and a trio of small but mighty tugboats move cargo vessels through the busiest port of Alaska, proving that size doesn't dictate power. (Repeat).

A sinkhole engulfs a Bronx residential street, growing so large that it swallows a van. Experts explain how heavy rain and old infrastructure caused this terrifying calamity. (Repeat).

A disastrous crane collapse falls across a landmark bridge in New York. (Repeat).

Tragedy strikes a beachside community when a condominium complex collapses in Miami, resulting in one of the deadliest engineering disasters in American history. Experts investigate and reveal potential flaws in the structure's flat slab construction. (Repeat).

Icy flood waters destroy a landmark bridge in Pennsylvania. (Repeat).

Disaster strikes a new railway bridge as a crane collapses in the middle of major construction in Italy. Experts investigate and uncover a compromise in balance with improperly positioned counterweights and a maneuver that resulted in catastrophe. (Repeat).

A tragic bridge collapse takes down a symbolic crossing and becomes one of Italy's deadliest engineering disasters; experts investigate and uncover years of slow deterioration to the structure's heavily corroded concrete-encased cables. (Repeat).

Icy flood waters destroy a landmark bridge in Pennsylvania. (Repeat).

Disaster strikes a new railway bridge as a crane collapses in the middle of major construction in Italy. Experts investigate and uncover a compromise in balance with improperly positioned counterweights and a maneuver that resulted in catastrophe. (Repeat).

A tragic bridge collapse takes down a symbolic crossing and becomes one of Italy's deadliest engineering disasters; experts investigate and uncover years of slow deterioration to the structure's heavily corroded concrete-encased cables. (Repeat).

Tragedy strikes a beachside community when a condominium complex collapses in Miami, resulting in one of the deadliest engineering disasters in American history. Experts investigate and reveal potential flaws in the structure's flat slab construction. (Repeat).

Search and rescue operations in arctic conditions rely on a special helicopter. (Repeat).

A helicopter tailor-made for extreme environments aids US Army rescue efforts in some of the harshest conditions, and a trio of small but mighty tugboats move cargo vessels through the busiest port of Alaska, proving that size doesn't dictate power. (Repeat).

Internet legends with epic skills. Included: the world's most incredible skin; tattooed toes; and a speed flier who lands inside a moving cable car. (Repeat).

The deaths of three cosmonauts while re-entering Earth's atmosphere; a CIA plan to use a space disaster as a cover to start World War III; and a NASA rover that uncovered clues to a murder. (Repeat).

Life on Mars; the universe's most destructive force; a starship found in the aurora borealis; and strange moon pigeons. (Repeat).

Neutrinos are the most mysterious particles in the universe, and they power some of the most explosive events in the cosmos. New discoveries reveal how these ghosts pass through objects undetected and why they could be the reason humans exist. (Repeat).

The team tells the story of where mankind and everything else came from. (Repeat).

Venus is a hellish alien world believed to be impossible to extraterrestrial life; but new discoveries reveal shocking evidence within its deadly atmosphere and on its strange surface, all pointing to a possible future for planet Earth. (Repeat).

Experts journey deep into space to examine asteroids and comets in the search to reveal the origins of the universe and the human race itself. (Repeat).

Some of the top experts seek to unravel the mystery of why Saturn's extensive ring system exists and if any of its many moons could harbor alien life. (Repeat).

Jeremy Wade explores a ground-breaking investigation of aircraft debris that may be linked to the disappearance of Amelia Earhart. Also, Jeremy looks into the discovery of an ancient, well-preserved anchor at the bottom of the Mediterranean Sea. (Repeat).

Jeremy Wade explores a ground-breaking scientific discovery that could change everything known about the most infamous shipwreck of all time, the Titanic. Also, a bag containing 54 severed human hands is discovered on the banks of a Siberian river. (Repeat).

Jeremy Wade explores an accident that involves a Russian nuclear submarine on a top-secret mission. Surprising details emerge surrounding the vessel's design. Also, scientists investigate ancient human remains emerging from a lake in Finland. (Repeat).

Jeremy Wade explores the puzzling disappearance of an Indonesian submarine, and the latest research into an underwater phenomenon may help piece together how it vanished. Also, a hoard of riches is found inside the wreck of an 18th-century Dutch vessel. (Repeat).

A deserted building has mysterious graffiti that might be connected to a dark secret; Looking into a military wasteland with a dark past. (Repeat).

Ghostly remnants of a remote Kentucky town suggests a forgotten tale of catastrophe and devastation. Then, experts investigate and uncover the dark and oppressive history of a deadly industrial mining complex. (Repeat).