NOVA

In Egypt's Sahara Desert, massive skeletons with strange skulls and gigantic teeth jut out from the sandy ground. This fossil graveyard, millions of years old, is known as the "Valley of the Whales." Now, paleontologists have unearthed a whole new species of ancient whale dating to 43 million years ago, and this predator wasn't just able to swim – it also had four legs and could walk. Follow scientists as they search for new clues to the winding evolutionary path of mammals that moved from the land into the sea to become the largest animals on Earth.

How were the giant stone heads of Rapa Nui–also known as Easter Island–carved and raised, and why? Since Europeans arrived on this remote Pacific island over 300 years ago, controversy has swirled around the iconic ancient statues and the history of the people who created them. Now, a new generation of researchers is overturning old theories, revealing the rich history, innovation, and resilience of the Rapanui people, and uncovering intriguing new evidence about where they–and their practice of monumental stone building–came from.

Explore the revolutionary engineering behind Paris's iconic landmark. Completed in just over two years for the 1889 World's Fair, the iron tower smashed the record for the tallest structure on Earth, ushering in a new age of global construction that reached for the skies. How did the engineers do it? Follow the innovations, successes, and failures that made one of the most famous buildings on the planet possible.

For decades, scientists have tried to unlock the secrets of ancient DNA. But life's genetic blueprint is incredibly fragile, and researchers have struggled to find DNA in fossils that could survive millions of years. Then, one maverick scientist had the controversial idea to look for DNA not in fossils or frozen ancient tissue – but in dirt. Join the hunt as scientists decipher the oldest DNA ever found, and reveal for the first time the genes of long-extinct creatures that once thrived in a warm, lush Arctic.

Can we harness the power of artificial intelligence to solve the world's most challenging problems without creating an uncontrollable force that ultimately destroys us? ChatGPT and other new A.I. tools can now answer complex questions, write essays, and generate realistic-looking images in a matter of seconds. They can even pass a lawyer's bar exam. Should we celebrate? Or worry? Or both? Correspondent Miles O'Brien investigates how researchers are trying to transform the world using A.I., hunting for big solutions in fields from medicine to climate change.

Explore the spectacular cosmic phenomenon of a total solar eclipse. In April 2024, the Moon's shadow is sweeping from Texas to Maine, as the U.S. witnesses its last total solar eclipse until 2044. This extraordinary astronomical event is plunging locations in the path of totality into darkness for more than four minutes – nearly twice as long as the last American eclipse in 2017. Learn how to watch an eclipse safely and follow scientists as they work to unlock secrets of our Sun – from why its atmosphere is hundreds of times hotter than its surface, to what causes solar storms and how we might one day predict them.

 Whether on social media or surfing the web, you probably share more personal data than you realize. That can pose a risk to your privacy – even your safety. But at the same time, big datasets could lead to huge advances in fields like medicine. Host Alok Patel leads a quest to understand what happens to all the data we're shedding and explores the latest efforts to maximize benefits – without compromising personal privacy.

How big is the universe? If it began with the Big Bang, will it also have an end? Is there life beyond our planet? Questions like these inspired the launch of Voyager I in 1977 and have driven innovative space research and exploration ever since. Trace the ground-breaking discoveries that have transformed our picture of the universe, from an age when we knew of no planets beyond our solar system, to today, when we have evidence of thousands and estimate trillions more. And follow the teams trying to solve two of the biggest mysteries in cosmology today: What are dark matter and dark energy?

Across the solar system, wild storms are raging. From globe-spanning dust storms, to monsoons of liquid methane, to monstrous storms with lightning bolts ten times more energetic than anything on Earth – our solar system is full of weird and wonderful weather. Explore the forces that create the truly awesome and extreme conditions found on our neighboring planets and moons.

From a dwarf planet that looks like a deflated football to a tiny moon with cliffs taller than Mt. Everest to the spectacular rings of Saturn, discover how the effects of gravity produce the amazing variety of weird worlds in our solar system.

All around our solar system, volcanoes are powerful shapers of worlds. Next door on Mars is Olympus Mons, a giant volcanic mountain more than twice the size of Mt. Everest. And closer to the Sun, thousands of volcanoes produce the toxic atmosphere that keeps Venus boiling. Then there's Jupiter's moon Io, the most volcanically active world in the entire solar system, and Saturn's moon Enceladus, where clues in its watery eruptions hint at the possibility of life. Discover the explosive forces that molded each of these worlds – and what makes the volcanoes right here on Earth so special. 

Ice might seem familiar to us on Earth, but out in the solar system, it can get quite exotic. From Uranus's ultra hot superionic ice, to glaciers of nitrogen ice on Pluto, to carbon dioxide snow on Mars, ice is a fundamental building block throughout our cosmic neighborhood. Visit some of the strange, frozen worlds of our solar system to discover why the ice here on Earth so special – and why we wouldn't be here without it.

The classic view of our solar system contains eight orderly planets, some with moons in neat orbits – but when we look closer, we discover a bunch of stuff missing from this simple, clockwork model. Wandering worlds that seem out of place, found in the gaps between and beyond the planets, offer clues that our cosmic neighborhood is far more dynamic than we once thought. From the meteorites that impact Earth, to a moon that orbits backwards, to an imposter lurking in the asteroid belt, these wandering worlds are rewriting what we know – and even how we think about – our solar system.

When we look at the world at the tiniest scales in the subatomic realm, things get weird – very weird. Welcome to the quantum universe, where particles can spin in two directions at once, observing something changes it, and something on one side of the galaxy can instantly affect something on the other, as if the space between them didn't exist. Buckle up for a wild ride through the discoveries that proved all of this to be true and paved the way for the digital technologies we enjoy today – and the powerful quantum sensors and computers of tomorrow.

Around the world, engineers are finding ingenious ways to amplify our abilities and senses – allowing us to access and shape the world way beyond our natural gifts. From helping a blind man see without the use of his eyes to building a sling so powerful it can shoot rockets into space, see why engineering just might be the closest thing to a superpower we humans have.

From the time our species first evolved, we've been on the move. Not content to stay in one place, we've imagined and invented and built our way from one place to the next. From deep sea subs to wind-resistant skyscrapers to next-gen space habitats, see how today's engineers are designing and building creative new ways for us to get all around – and even off – our planet.

Thousands of years of human innovation have allowed us to shape the environment to improve lives. The consequences of our activities are not always benign – but there are solutions. From electrifying aviation, to building robots to protect threatened coral reefs, a new generation of engineers is finding creative solutions to some of our most critical environmental challenges.

After the devastating 2019 fire at Notre Dame, two mysterious sarcophaguses were discovered under the cathedral's stone floor. Who is buried in them, and what secrets will these coffins reveal? Follow a team of archaeologists and historians as they attempt to solve centuries-old mysteries using the latest scientific investigation techniques. What can forensic analysis of the remains reveal about one of the world's most famous cathedrals and those who devoted their lives to it?

Now at a crossroads for the future of the Gulf of Maine and our oceans, Indigenous peoples and scholars practice climate resilience and adaptation, scientists track developments, and entrepreneurs find new ways to make a living from the sea.