A group of orphaned lion cubs are facing an uncertain future. If they're to survive into adulthood, they will have to convince their reluctant aunt to share her kill with them.

Hostile Lioness Withholds Food From Hungry Orphaned Cubs (3:09)

It's 1942 and the USS Silversides, a U.S. submarine submerged in the Pacific, is frantically trying to dodge depth charges dropped by a Japanese warship. Even a near miss could be catastrophic.

Why Depth Charges Don't Have to Touch a Submarine to Sink It (3:52)

A group of five adolescent male lions - dubbed the Musketeers - are wandering the desert looking to find their own kingdom. They come across a lioness, but not all seem interested in settling down.

Five Young Lion Brothers Mate With One Lioness (3:44)

During spawning season, calamari squid become vulnerable in the shallow waters. But they do have one weapon that helps improve their odds - lightning fast jet propulsion.

How Spawning Squid Offer a Buffet for Predators (2:58)

In a sandy gully, a school of razorfish are being stalked by an invisible predator and a master of disguise: the crafty cuttlefish.

A Clever Cuttlefish Goes in for the Kill (1:55)

They might be delicious to us but in the ocean, calamari squid are formidable predators, using concealed tentacles which shoot out toward any prey within a three-foot radius.

The Remarkable Way Calamari Squid Catch Their Prey (1:37)

A marauding polar bear is about to be returned to the the wild, as far away as possible from the town of Churchill. To do that, the conservation team will need to tranquilize him, and then airlift him by helicopter.

A Polar Bear Released Back Into the Wild by Helicopter (2:12)

The San Gabriel Mountains lure lots of Angelenos looking for some quiet seclusion. One of the more famous was Leonard Cohen who spent five years there, searching for peace of mind.

This Footage of Jaguars in Panama Could Save Their Lives (3:39)

Conservationists have tracked down a polar bear who has taken to venturing into nearby Churchill. The next step is to airlift him by helicopter to a holding facility, and then back into the wild.

How Churchill Protects Itself From Polar Bears (2:28)

Vying with the Russians for space supremacy, the U.S. successfully launches Apollo 8. Once in orbit, astronaut William Anders takes one of the most legendary photographs of all time.

This Apollo 8 Astronaut Took the Famous "Earthrise" Photo (2:43)

Tiger cub Kumal is entirely dependent on his mother to hunt prey. He also relies on his father for protection against intruders. Someday he will need to provide for himself, but for now, the support of his parents will do.

Mother Tiger Makes Speedy Kill to Feed Cubs (2:02)

Famed fisherman and adventurer Andy Coetzee thinks he may have snared a giant barracuda. He hasn't, but he's caught another interesting and prized fish--the West African Tarpon.

An Intense Struggle to Catch a Giant West African Tarpon (3:10)

Hippos were once believed to be related to whales. They're both mammals, they both sleep underwater, and they both rise to breathe in their sleep, without waking.

Why People Believed Hippos Were Related to Whales (1:31)

Rising sea levels are threatening to flood Miami. In fact, some scientists estimate that the entire city could be underwater by the end of the 21st century.

The Biggest Threat Facing the City of Miami (2:19)

The maze of lagoons in Loango National Park, in Gabon, isn't just a good place to hunt barracudas--it's also an ancient migratory route that leads to their ancestral breeding waters.

Why These Lagoons Are Full of Giant Barracuda (2:44)

The reddish hues of the vast dunes of the Namib Desert in southern Africa are a result of concentrations of iron in the sand. Over time, the air oxidizes the sand, causing it to rust.

Are the Sands of the Namib Desert Really Rusting? (1:32)

South African fisherman Andy Coetzee has his eyes set on a giant perch--a massive freshwater predator fish indigenous to the waters of Uganda. But just as he catches one, a nearby crocodile tries to get in on the action.

Fishing for Perch in Nile Crocodile-Filled Waters (3:08)

Fisherman and adventurer Andy Coetzee is going traditional with his bid to snare a giant perch: He's using live bait and his tried-and-true wooden Scarborough.

Catching a Giant 30-lb. Perch With a Wooden Reel (2:37)

Fisherman Andy Coetzee is in the middle of a dangerous dive, in the shark-filled waters of the Indian Ocean. He's on the lookout for a fierce and elusive giant predator: the dogtooth.

Braving Shark-Infested Waters for a Look at This Big Fish (3:05)

Arriving in the Chesapeake Bay, the early American inhabitants' first order of business would have been to craft weapons to defend themselves. They would need them, with terrifying predators like the short-faced bear on the prowl.

Terrifying Mammals That May Have Greeted Early Humans in America (2:32)

On an island off the east coast of Maryland, a stone spearpoint sticking out of a coastal cliff stuns archaeologists. It asks a big question: Could humans have arrived in America 5,000 years earlier than we thought?

The Startling Alternative Theory of How Humans Arrived in America (2:51)

Hydrogen cyanide is a molecule that appears to be at the heart of the creation of life. To create it, scientists need a burst of energy the equivalent of an endless lightning storm.

This Molecule Could Explain the Origin of Life (3:28)

13.8 billion years ago, the universe began with a big bang and the atoms it created would find their way into everything: from celestial stars to the human body.

We're All Made of Stardust. Here's How. (3:29)

In Deception Valley, giant salt flats the size of Portugal are a major boon to the Botswanan economy. Today, Botswana relies heavily on extracting, manufacturing and exporting mineral commodities, such as soda ash.

You Won't Believe the Size of Botswana's Salt Flats (2:43)

The harsh climate of Deception Valley, a remote section of the Kalahari, deters people from living there. As a result, it's become one of the most pristine wildlife habitats in the world.

Why Deception Valley's Deadly Heat is Good for Wildlife (1:39)

The Sani Pass, which cuts through the mountain peaks between South Africa and Lesotho, is known for being a death-defying experience. Its steep track is difficult when dry, almost impossible when it snows.

One of the Most Dangerous Mountain Passes in the World (1:43)

In the Karoo region of South Africa, mysterious spiral shapes carved into the ground have attracted conspiracy theorists who liken them to the famous geoglyphs in the Nazca desert.

What Created These Strange Geoglyphs in South Africa? (1:55)

About 220,000 years ago, a meteor slammed into a corner of South Africa creating the Tswaing Crater. Today, it's a hotbed of wildlife and exotic vegetation, drawing tourists from all over the world.

The Most Beautiful View of South Africa's Tswaing Crater (2:25)

In one of his final on-camera appearances, iconic physicist Stephen Hawking issued a warning to humanity about the existential threats we face and how our survival depends on colonizing another planet.

Stephen Hawking's Stark Warning for Humans to Leave Earth (3:05)

In 1991, eight people spent two years living in giant, sealed-off glass domes, deep in the Arizona desert. This project, known as Biosphere 2, could be an important case study that helps us survive on an inhospitable alien planet.

This Science Experiment Could Help Us Live on Another Planet (2:57)