During World War I, the Allies and Germans repeatedly struggled to break the hideous stalemate of trench warfare. In the winter of 1916, Allied engineers devised a massive surprise attack: over 1 million pounds of explosives hidden in secret tunnels driven under German lines. Building the tunnels was desperate work, with tunnelers at constant risk from flooding, cave-ins, and enemy digging teams. In June of 1917, the planted mines at Messines were simultaneously triggered, killing an estimated 10,000 German troops instantly. Now, archaeologists are revealing the extraordinary scale and risks of the Allied tunneling operations in one of the biggest excavations ever undertaken on the Western Front. “Secret Tunnel Warfare” opens a unique window on the frenzy of Allied mining activity that led up to the attack and its bitter aftermath.

Four and a half billion years ago, the young Earth was a hellish place—a seething chaos of meteorite impacts, volcanoes belching noxious gases, and lightning flashing through a thin, torrid atmosphere. Then, in a process that has puzzled scientists for decades, life emerged. But how? NOVA joins mineralogist Robert Hazen as he journeys around the globe. From an ancient Moroccan market to the Australian Outback, he advances a startling and counterintuitive idea—that the rocks beneath our feet were not only essential to jump-starting life, but that microbial life helped give birth to hundreds of minerals we know and depend on today. It's a theory of the co-evolution of Earth and life that is reshaping the grand-narrative of our planet’s story.

Tiny, transparent, and threatened, krill are crucial to the Antarctic ecosystem. But the population of krill is crashing for reasons that continue to baffle the experts. A leading theory says that krill’s life cycle is driven by an internal body clock that responds to the waxing and waning of the Antarctic ice pack, and as climate change alters the timing of the ice pack, their life cycle is disrupted. To test it, NOVA travels on the Polarstern, a state-of-the-art research vessel, to the frigid ice pack in the dead of winter. From camps established on the ice, scientists dive beneath the surface in search of the ice caves that shelter juvenile krill during the winter. There, they hope to discover what’s causing the krill to vanish and, ultimately, how the shifting seasons caused by climate change could disrupt ecosystems around the world.

On April 25, 2015, a devastating earthquake rocked Nepal. As it ripped across the Himalayas, it wiped out villages and left thousands dead. Hear the harrowing stories of the Nepalese people who lived near the epicenter and of survivors trapped on Everest. Through dramatic eyewitness footage, expert interviews, and stunning graphics, NOVA reveals the anatomy of this megaquake while scientists race to answer urgent questions—Is another big one just around the corner? What can we learn from the deadly combination of earthquakes and landslides? And can we rebuild to survive the next big one?

On a summer’s night, there’s nothing more magic than watching the soft glow of fireflies switching on and off. Few other life forms on land can light up the night, but in the dark depths of the oceans, it’s a different story: nearly 90% of all species shine from within. Whether it’s to scare off predators, fish for prey, or lure a mate, the language of light is everywhere in the ocean depths, and scientists are finally starting to decode it. NOVA and National Geographic take a dazzling dive to this hidden undersea world where most creatures flash, sparkle, shimmer, or simply glow. Join deep sea scientists who investigate these stunning displays and discover surprising ways to harness nature’s light—from tracking cancer cells to detecting pollution, lighting up cities, and even illuminating the inner workings of our brains.

Memory is the glue that binds our mental lives. Without it, we’d be prisoners of the present, unable to use the lessons of the past to change our future. From our first kiss to where we put our keys, memory represents who we are and how we learn and navigate the world. But how does it work? Neuroscientists using cutting-edge techniques are exploring the precise molecular mechanisms of memory. By studying a range of individuals ranging—from an 11-year-old whiz-kid who remembers every detail of his life to a woman who had memories implanted—scientists have uncovered a provocative idea. For much of human history, memory has been seen as a tape recorder that faithfully registers information and replays intact. But now, researchers are discovering that memory is far more malleable, always being written and rewritten, not just by us but by others. We are discovering the precise mechanisms that can explain and even control our memories. The question is—are we ready?

He was stalked, attacked and left to die alone. Murdered more than 5,000 years ago, Otzi the Iceman is Europe’s oldest known natural mummy. Miraculously preserved in glacial ice, his remarkably intact remains continue to provide scientists, historians, and archeologists with groundbreaking discoveries about a crucial time in human history. But in order to protect him from contamination, this extraordinary body has been locked away, out of reach, in a frozen crypt—until now. NOVA joins renowned artist and paleo-sculptor Gary Staab as he has been granted rare access into the Iceman’s frozen lair. Gary has been charged with creating an exact replica of the mummy, which scientists and the public alike can then study up close and in person. As we see the Iceman reborn from 3D printing, resin, clay and paint, new revelations about Otzi’s life and legacy come to light, including surprising secrets hidden in his genetic code.

Machines are everywhere. They run our factory assembly lines and make our coffee. But humanoid robots—machines with human-like capabilities—have long been the stuff of science fiction. Until now. Fueled by an ambitious DARPA challenge, the race is on to design a robot that can replace humans in disaster relief situations. Follow the robots and the engineers that program them as they strive to make their way out of the lab and into the real world. But how capable are they, really? How close are we to a future where humanoid robots are part of our everyday lives? And what will the future look like with robots that can do a human’s job? NOVA investigates the cutting-edge technologies that are advancing robotics—and the enormous challenges that robots still face.

Uncover the truth behind the legendary Vikings and their epic journey to the Americas.

Alzheimer's ravages the minds of over 40 million victims worldwide. Join scientists as they untangle the cause of this tragic illness and go behind the scenes of major drug trials to discover the therapies that may slow and even prevent the disease.

Explore how newly established wildlife corridors offer hope to endangered species.

Engineers race to rescue the Gay Head Lighthouse on Martha's Vineyard from the ocean's erosion.

Engineers and World War II historians investigate Hitler's fearsome bank of "superguns."

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

How the science of learning may change education for all children.

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.

Gold, bronze, iron, steel... metals are pillars of our civilization, but what makes them so special? Discover their unique properties and explore how our mastery of metals has led us from the stone age to today's hi-tech world.

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.