Colossal explosions shake a remote corner of the Siberian tundra, leaving behind massive craters. In Alaska, a huge lake erupts with bubbles of inflammable gas. Scientists are discovering that these mystifying phenomena add up to a ticking time bomb, as long-frozen permafrost melts and releases vast amounts of methane, a potent greenhouse gas. What are the implications of these dramatic developments in the Arctic? Scientists and local communities alike are struggling to grasp the scale of the methane threat and what it means for our climate future.

Scott Burnett is “Scatman”—an Australian ecologist on the trail of the secrets of poop. By identifying and analyzing animal scat for DNA and hormones, he discovers essential details of their behavior, how they fit in the ecosystem, and even how to protect them. From the mysterious cubic poop of wombats to the precious pink waste of whales, join scientists as they explore nature’s smelliest secrets.

Sir David Attenborough investigates a unique site in southern England where amateur fossil hunters uncovered giant mammoth bones and evidence of Neanderthals. A team of paleontologists and archaeologists soon discover that the site preserves rare evidence of the extinct beasts and early human inhabitants of Britain dating to over 200,000 years ago.

Follow the dramatic personal journey of Hugh Herr, a biophysicist working to create brain-controlled robotic limbs. At age 17, Herr’s legs were amputated after a climbing accident. Frustrated by the crude prosthetic limbs he was given, Herr set out to remedy their design, leading him to a career as an inventor of innovative prosthetic devices.

Follow three women at risk of developing Alzheimer’s as they join a groundbreaking study to try to prevent the disease – sharing their ups and downs, anxiously watching for symptoms, and hoping they can make a difference.

Striking new fossils paint a picture of life right before the asteroid impact.

Scientists use new fossils to reconstruct the day the dinosaurs died.

How could a single ship cause a major supply chain crisis around the globe?

Ancient footprints provide new evidence of humans and extinct giant beasts of the Ice Age.

Follow the dramatic story of NASA’s James Webb Space Telescope – the most complex machine ever launched into space – in hopes of peering deeper back in time than ever before and answering some of astronomy’s biggest questions.

Rising seas and sinking land threaten to destroy Venice. Can the city’s new hi-tech flood barrier save it? Discover the innovative projects and feats of engineering designed to stop this historic city from being lost to future generations.

Almost 40 years after the discovery of HIV, could we be on the verge of ending the AIDS epidemic in America? As of 2019, in the U.S., there were only 34,000 new cases of the disease—a feat that once seemed near-impossible to achieve. How did scientists and the public health community tackle one of the most elusive deadly viruses to ever infect humans? Can innovative drugs bring new infections to zero? This is the story of an incredible scientific achievement and the public health work that still needs to be done to end HIV in America.

In police departments and courts across the country, artificial intelligence is being used to help decide who is policed, who gets bail, how offenders should be sentenced, and who gets parole. But is it actually making our law enforcement and court systems fairer and more just? This timely investigation digs into the hidden biases, privacy risks, and design flaws of this controversial technology.

Hallucinogenic drugs—popularly called psychedelics—have been used by human societies for thousands of years. Today, scientists are taking a second look at many of these mind-altering substances–both natural and synthetic–and discovering that they can have profoundly positive clinical impacts, helping patients struggling with a range of afflictions from addiction to depression and PTSD.

Lionfish – long prized in home aquariums – have invaded the Atlantic, and are now one of the ocean’s most successful invasive species, wreaking havoc in waters across the globe. Join ocean explorer Danni Washington on a journey to find out how they took over, why they’re doing so much damage, and what can be done about it. These fascinating creatures are a window into the impacts of invasive species in a globalized world where human activity is an increasingly powerful evolutionary force.

One of the world’s greatest ancient enigmas, the Nazca lines are a dense network of criss-crossing lines, geometric shapes, and animal figures etched across 200 square miles of Peruvian desert. Who created them and why? Ever since they were seen from the air in the 1940s, scholars and enthusiasts have raised countless theories about their purpose. Now, archaeologists have discovered hundreds of long-hidden lines and figures as well as evidence of ancient rituals, offering new clues to the origins and motivations behind the giant desert symbols.

From Bitcoin to NFTs, crypto is making headlines. But what exactly is it, and how does it work? Experts go beyond the hype and skepticism to unravel the social and technological underpinnings of crypto – exploring how it came to be and why this new technology may change more than just money.

Zero and infinity. These seemingly opposite, obvious, and indispensable concepts are relatively recent human inventions. Discover the surprising story of how these key concepts that revolutionized mathematics came to be – not just once, but over and over again as different cultures invented and re-invented them across thousands of years.

In April 2019, the world watched as a devastating fire almost destroyed Paris’s iconic Notre Dame Cathedral. Go behind the scenes with a team of engineers, masons, and timber workers tackling the daunting challenges of restoring the historic landmark.