NOVA

Today, Earth is enveloped by a thin veil of gas, a narrow band of atmosphere that protects a world covered in lush green vegetation, deep blue oceans, and abundant life. But 4.5 billion years ago, Earth was a very different place: a hellscape of molten lava and barren rock, under relentless bombardment from meteors, and with no atmosphere whatsoever. So how did our familiar blue sky come to be? Breathtakingly realistic animations and a chorus of science experts reveal how the primordial inferno first gave rise to an orange-hued cauldron of toxic gasses that would be deadly to us today. Witness how the first drops of rain splashed down on the searing planet, setting the stage for the evolution of life. And discover how life itself helped create the air we all breathe today.

700 million years ago, Earth was a giant snowball cloaked in ice from pole to pole – a global deep freeze that held the planet in a stranglehold, threatening the survival of the earliest complex life. How did life manage to hold on in this forbidding world? Leading scientists investigate how this catastrophe may have become a catalyst for life to evolve in creative new ways as it bounced back from the brink – setting the stage for the astonishing complexity we see today.

For billions of years, life teemed in the oceans of planet Earth while the land was desolate and inhospitable. So, how did life make the leap to land? Scientists explore how some of the earliest life emerged and invaded a barren, rocky landscape, eventually transforming it into a verdant, green world. Gripping visual effects reveal an alien landscape dominated by towering fungi before the arrival of plants. Witness how the first plants made landfall and partnered with fungi to create soil that would sustain them. And discover how, once life emerged on land, it fundamentally altered the very ground it grew on.

252 million years ago, the most devastating mass extinction of all time abruptly wiped out around 90% of all species on Earth. The culprits were the biggest volcanic eruptions the world has ever seen, emitting some 700 thousand cubic miles of magma and rock. Volcanic gasses permeated the atmosphere and acidified the oceans, while toxic gasses destroyed the ozone layer, bathing the planet in destructive UV radiation. The event – now called "The Great Dying" – came close to wiping out all life on the planet. Follow scientists as they piece together geologic evidence from the deep past and clues from today's ecosystems to discover how life made it through and evolved into the astonishing variety we see around us today.

The story of Earth can only be told because now, 4.5 billion years into its existence, a technological and self-aware animal species roams its surface, able to study the very planet that gave rise to it. But how exactly did Earth give rise to humans? Through stunningly realistic animation, witness the cataclysmic asteroid strike that wiped out the dinosaurs, the tumultuous changing climates that allowed early primates to spread across the planet, and the geologic events that created the conditions for the evolution of an animal that walks upright on two legs. Explore the power and paradox of humanity's profound impact on our planet and ponder the question of how we may shape its future.

In the span of just a few decades, China has transformed into a science and technology superpower. But how did it get here and where is it headed? Take an insider's tour of high-profile tech companies and labs that are driving China's meteoric rise to the forefront of global innovation. How does China innovate? What drives its bid for technological supremacy? And what does its rise mean for the future of the global economy?

Malaria is one of humanity's oldest and most devastating plagues. In many parts of the world, it remains an ever-present scourge that sickens or kills millions of people each year. What if it could finally be defeated? Now, scientists may be on the verge of a breakthrough with a promising vaccine in the final stages of testing and approval. Follow researchers on a quest to deliver humankind from one of the world's deadliest diseases.

Many descendants of enslaved people have little record of their family's ancestry. Follow one family's quest to discover their lost history, and see how science and genealogy can help rebuild a family tree broken by slavery. Join filmmaker Byron Hurt at his extended family reunion as they celebrate the joy of family in the African diaspora and discover new details of their history that they thought were lost forever.

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.