Season 44

From 9/11 to today’s crowd-sourced violence, trace how terrorists’ strategies have evolved.

Follow our ancient ancestors’ footsteps out of Africa and into every corner of our planet.

Join engineers as they build a massive new railway deep beneath the streets of London.

Gemstones like diamonds, rubies, opal and jade are the ultimate treasures. Delve into Earth's depths to discover how these precious stones are forged and what explains the unique allure of each captivating gemstone.

Drill down to discover how Earth's natural treasures provide bountiful energy to power our modern world yet are also driving us to seek new, cleaner alternatives that can help us keep the lights on.

The towering Himalayas were among the last places on Earth that humanity settled. Scaling sheer cliff sides, a team of daring scientists hunts for clues to how ancient people found their way into this forbidding landscape and adapted to survive the high altitude. They discover rock-cut tombs filled with human bones and enigmatic artifacts, including gold masks and Chinese silk dating back thousands of years, and piece together evidence of strange rituals and beliefs designed to ward off the restless spirits of the dead.

Five years after the earthquake and tsunami that triggered the unprecedented trio of meltdowns at the Fukushima Daiichi nuclear power plant, scientists and engineers are struggling to control an ongoing crisis. What’s next for Fukushima? What’s next for Japan? And what’s next for a world that seems determined to jettison one of our most important carbon-free sources of energy? Despite the catastrophe—and the ongoing risks associated with nuclear—a new generation of nuclear power seems poised to emerge the ashes of Fukushima. NOVA investigates how the realities of climate change, the inherent limitations of renewable energy sources, and the optimism and enthusiasm of a new generation of nuclear engineers is looking for ways to reinvent nuclear technology, all while the most recent disaster is still being managed. What are the lessons learned from Fukushima? And with all of nuclear’s inherent dangers, how might it be possible to build a safe nuclear future?

Explore the hidden world of energy storage and how it holds the keys to a greener future.

Join pioneering shipbuilders as they embark on a feat of maritime engineering.

The centuries-old tradition of folding two-dimensional paper into three-dimensional shapes is inspiring a scientific revolution. The rules of folding are at the heart of many natural phenomena, from how leaves blossom to how beetles fly. Engineers and designers are applying its principles to reshape the world around us—and even within us, designing new drugs, micro-robots, and future space missions.

From derailments to head-on collisions to drivers killed at road crossings, deadly train accidents claim dozens of lives each year. But just how unsafe are the railroads? NOVA investigates recent rail tragedies and advances in train tech that could help prevent them, taking a special look at Japan’s superefficient bullet trains, which have a perfect safety record. What would it take to usher in a new golden age of safer, faster, more modern and reliable train travel?

The Lithuanian city of Vilna, known also as the “Jerusalem of the North”, was one of the most important Jewish centers in the world until World War II, when the Nazis murdered about 95% of its Jewish population. Now, an international team of archaeologists is excavating the remains of its Great Synagogue and searching for a lost escape tunnel dug by Jewish prisoners inside a Nazi execution site.

Engineers race to build a massive dome to contain the crumbling remains of the reactor.

For over 1000 years, chariots thundered across China's battlefields - dominating warfare longer than anywhere else on earth. Now, archaeological findings enable a team of experts to reconstruct and test China's first super-weapon.

NOVA investigates what happened in Flint, Michigan when local officials changed the city’s water source to save money, but overlooked a critical treatment process. As the water pipes corroded, lead leached into the system, exposing the community—including thousands of children—to dangerous levels of poison. NOVA uncovers the science behind this manmade disaster.

On August 21, 2017, millions of Americans will witness the first total solar eclipse to cross the continental United States in 99 years. While hordes of citizens prepare to flock to the eclipse’s path of totality, scientists, too, are staking out spots for a very different reason: to investigate the secrets of the sun’s elusive atmosphere.

Stonehenge is the grandest and most enigmatic of Europe’s prehistoric monuments, and has inspired countless theories to explain who built it and why. Join NOVA as we reveal intimate details of the Stonehenge people and why their power began to fade soon after they raised the mighty stones.

Aiming to skim less than 2000 miles above the cloud tops, no spacecraft has ever gone so close to Saturn, and hopes are high for incredible observations that could solve major mysteries about the planet’s core. Join NASA engineers for the tense and triumphant moments as they find out if their bold reprogramming has worked, and discover the wonders that Cassini has revealed over the years.

Once upon a time, knighthood was serious business, and for countless medieval fighters, their armor was what stood between life and death. NOVA challenged a blacksmith and master armorer to recreate parts of an elite armor. We trace their journey as they rediscover centuries-old metalworking secrets, then put their new armor to the ultimate test against a period musket.

The Forbidden City is the world’s biggest and most extravagant palace complex ever built. For five centuries, it was the power center of imperial China and survived wars, revolution, fires, and earthquakes. How did the Ming Emperor’s workforce construct its sprawling array of nearly 1,000 buildings and dozens of temples in a little over a decade?

NOVA follows a team of volcano sleuths as they embark on a worldwide hunt for an elusive volcanic mega-eruption that plunged medieval Earth into a deep freeze. They look for the signature of a volcanic eruption big enough to have blasted a huge cloud of ash and sulfuric acid into the atmosphere, which chilled the entire planet. Across the globe, it turned summer into winter.

Devastating hurricanes struck the U.S. mainland and Caribbean islands in 2017. But they weren’t the first. The Great Hurricane of 1780 took nine days to blast its way across the Caribbean, killing at least 20,000—the highest known death toll of any single weather event in history. What made this superstorm so deadly?

All over the world, scientists are discovering traces of ancient floods on a scale that dwarfs even the most severe flood disasters of recent times. What triggered these cataclysmic floods, and could they strike again? In the Channeled Scablands of Washington State, the level prairie gives way to bizarre, gargantuan rock formations.

From lobster claws and dog teeth to bee stings and snake fangs, every creature depends on a weapon. But some are armed to extremes that make no practical sense—whether it’s bull elks with giant 40-pound antler racks or tiny rhinoceros beetles with horns bigger than their body. What explains giant tusks, horns, and claws that can slow an animal down and even impair health and nutrition? NOVA investigates the riddle of outsize weaponry and uncovers a bold new theory about what triggers an animal arms race. In creatures as varied as dung beetles and saber-toothed tigers, shrimp and elephants, the same hidden factors trigger the race and, once started, these arms races unfold in exactly the same pattern. Join scientists as they crack the secret biological code that underlies nature’s battleground.

Watch astonishing tests of avian aptitude: parrots that can plan for the future, jackdaws that can “read” human faces, and crows that can solve multi-step puzzles with tools like pebbles, sticks, and hooks. Could these just be clever tricks, based on instinct or triggered by subtle cues from their human handlers?

66 million years ago, a seven-mile-wide asteroid collided with Earth, triggering a chain of events that coincide with the end of the dinosaurs. But experts have long debated exactly what happened when the asteroid struck and how the giant beasts met their end. Now, scientists have uncovered compelling new clues about the catastrophe.