NOVA - Season 40

The Vikings were among the fiercest warriors of all time. Yet only a select few carried the ultimate weapon of their era: the feared Ulfberht sword. Fashioned using a process that would remain unknown to the Vikings' rivals for centuries, the Ulfberht was a revolutionary high-tech tool as well as a work of art. Considered one of the greatest swords ever made, it remains a fearsome weapon more than a millennium after it last saw battle. But how did Viking sword makers design and build the Ulfberht, and what was its role in history? Now, NOVA uses cutting edge science and old-fashioned detective work to reconstruct the Ulfberht and finally unravel the "Secrets of the Viking Sword."

Learn how modern forensics can send innocent men and women to prison - and sometimes even to death row.

A remote, bleak speck of rock in the middle of the Pacific, Easter Island, or Rapa Nui, has mystified the world ever since the first Europeans arrived in 1722. How and why did the ancient islanders build and move nearly 900 giant statues or moai, weighing up to 86 tons? And how did they transform a presumed paradise into a treeless wasteland, bringing ruin upon their island and themselves? NOVA explores controversial recent claims that challenge decades of previous thinking about the Islanders, who have been accused of everything from ecocide to cannibalism. Among the radical new theories is that the islanders used ropes to "walk" the statues upright, like moving a fridge. With the help of an accurate 15-ton replica statue, a NOVA team sets out to test this high-risk, seemingly unlikely theory—serving up plenty of action and surprises in this fresh investigation of one of the ancient world's most intriguing enigmas.

Witness the exhilarating moments of Curiosity's Mars landing - and the spectacular discoveries afterward.

Find out what can we do to prepare for the inevitable disaster following a volcanic eruption in Iceland.

Find out what happened when the first modern humans encountered Neanderthals 60,000 years ago.

Discover the technologies that make drones so powerful, propelling us toward a new chapter in aviation history.

Follow investigators' efforts to determine what really happened to Lindbergh's baby - and why.

Follow a team of experts who build and test two accurate replicas of Egyptian royal chariots.

Witness a groundbreaking special that reveals a spectacular new space-based vision of Earth.

Learn how much science can tell us about a brain at risk for violence.

A blinding flash of light streaked across the Russian sky, followed by a shuddering blast strong enough to damage buildings and send more than 1,000 people to the hospital. On the morning of February 15, 2013, a 7,000-ton asteroid crashed into the Earth's atmosphere. According to NASA, the Siberian meteor exploded with the power of 30 Hiroshima bombs and was the largest object to burst in the atmosphere since the Tunguska event of 1908, which was also in Siberia and left few eyewitnesses or clues. This time, the event was captured by digital dashboard cameras, now common in Russian autos and trucks. Within days, NOVA crews joined impact scientists in Russia as they hunted for clues about the meteor's origin and makeup. From their findings, it's clear we came close to a far worse disaster, which NOVA sets in perspective by looking at greater explosions from the past, including Tunguska and the asteroid that wiped out the dinosaurs 65 million years ago. "Meteor Strike" asks: Is our solar system a deadly celestial shooting gallery with Earth in the crosshairs? And what are the chances that another, more massive asteroid is heading straight for us?

In 1900, a storm blew a boatload of sponge divers off course and forced them to take shelter by the tiny Mediterranean island of Antikythera. Diving the next day, they discovered a 2,000 year-old Greek shipwreck. Among the ship's cargo they hauled up was an unimpressive green lump of corroded bronze. Rusted remnants of gear wheels could be seen on its surface, suggesting some kind of intricate mechanism. The first X-ray studies confirmed that idea, but how it worked and what it was for puzzled scientists for decades. Recently, hi-tech imaging has revealed the extraordinary truth: this unique clockwork machine was the world's first computer. An array of 30 intricate bronze gear wheels, originally housed in a shoebox-size wooden case, was designed to predict the dates of lunar and solar eclipses, track the Moon's subtle motions through the sky, and calculate the dates of significant events such as the Olympic Games. No device of comparable technological sophistication is known from anywhere in the world for at least another 1,000 years. So who was the genius inventor behind it? And what happened to the advanced astronomical and engineering knowledge of its makers? NOVA follows the ingenious sleuthing that finally decoded the truth behind the amazing ancient Greek computer.

What can Australia reveal about how Earth was born and how life took hold? Join NOVA and host Dr. Richard Smith as they journey back to the very beginning of the Australian story in "Awakening." The first stop is Western Australia, around four and a half billion years ago, where we encounter an Earth shortly after its fiery birth. Hidden in the red hills of Australia are clues to the mysteries of when the Earth was born, how life first arose, and how it transformed the planet. Experts unveil how the earliest forms of life—an odd assortment of bacterial slime—flooded the atmosphere with oxygen, sparking the biological revolution that made animal life possible. It is the beginning of the great drama of life on Earth.

How did life storm the beaches and dominate planet Earth? Ancient Australian fossils offer clues in "Life Explodes." Half a billion years ago, Australia was still part of the super-continent Gondwana. The oceans were teeming with weird and wonderful animals, but the world above the waves remained an almost lifeless wasteland. All that was about to change, though. Host Richard Smith introduces Earth's forgotten pioneers: the scuttling arthropod armies that invaded the shores and the waves of green revolutionaries whose battle for the light pushed plant life across the face of a barren continent. Evolution continued underwater as well, with armor-plated fish experimenting with teeth, jaws, sex, and lungs. NOVA's prehistoric adventure continues with four-legged animals walking onto dry land—and the planet poised for disaster.

"Monsters" begins Down Under at the dawn of the Age of Dinosaurs. Host Richard Smith comes face-to-face with the previously unknown reptilian rulers of prehistoric Australia. NOVA resurrects the giants that stalked the Great Southern Land and discovers that some of these animals were among the largest ever to have walked the Earth. Others were some of the most dangerous. In the dry desert heart, scientists unearth an ancient inland ocean full of sea monsters. Opal fossils of some of these beasts paint a colorful picture of the exotic seascape, where long-necked plesiosaurs snacked on shelled creatures that grew as large as truck tires. The most fearsome was Kronosaurus, with a skull twice as long as T. rex. But reptiles didn't have the world all to themselves. Mammals like the enigmatic platypus lived alongside them, ready for their moment in the sun.

In the wake of the catastrophic asteroid impact believed to have wiped out the dinosaurs, Australia was set adrift on a lonely voyage across southern seas. With host Richard Smith, NOVA travels the walkabout continent to uncover how it became the strange land it is today. In this final episode, "Strange Creatures," NOVA traces the last 65 million years, revealing the events that shaped the Australia we know today. Prehistoric jungles retreated, replaced by eucalypt forests, grasslands, and deserts. When humans first arrived, giant marsupials dominated the land, and the Great Barrier Reef was yet to form. This is a tale of calamity and conquest; how a conspiracy of climate, biology, and geology shaped the Earth we now call home.

Technology to capture the 2 terroists in Boston.