David Condon

Since it explored Pluto in 2015, the New Horizons spacecraft has been zooming toward NASA's most distant target yet. Join the mission team as the probe attempts to fly by Ultima Thule, an object 4 billion miles from Earth.

Researchers seek solutions to contain the rising acidity levels that are threatening the world's oceans.

Evolving over 220 million years ago, lizards are both terrestrial and aquatic. Found everywhere in the world, they are cold-blooded, carnivores and herbivores with over 6,000 species including: Chameleons, Chuckwallas, Desert Iguanas, Frill-Necked Lizards, Beaded Lizards (which are venomous), Geckos, Gila Monsters and Komodo Dragons. They are older than time itself and will long outlive mankind.

With access to the scientists and engineers responsible for the Curiosity rover's on-the-ground experiments, NOVA captures its landing on Mars

The Vikings were the most ferocious warriors of the Middle Ages. Especially fearsome were the select few who wielded a formidable weapon: a light, razor sharp, virtually indestructible sword with its maker's name, Ulfberht, inlaid along the blade.

It contains 99.9 percent of all the matter in our solar system and sheds hot plasma at nearly a million miles an hour. The temperature at its core is a staggering 27 million degrees Fahrenheit. It convulses, it blazes, it sings. You know it as the sun. Scientists know it as one of the most amazing physics laboratories in the universe.

In a race against developers in the Rocky Mountains, paleontologists uncover a unique fossil site packed with astonishingly well-preserved bones of mammoths, mastodons, and other giant extinct beasts. The discovery opens a highly focused window on the vanished world of the Ice Age in North America.

As a general, he had fought to preserve the Union. As president, he helped to oversee the transformation from union to nation. As a former president, he was the embodiment of the very idea of national union, and of America's entry onto the world stage. As a dying general, he was the symbol of the nation's greatest and most traumatic war. The story of Ulysses S. Grant's life, from his first days on the Ohio frontier to his last days out-writing death in the Adirondacks, is an endlessly fascinating one. Few public figures have ever held a such a firm grip on the American popular imagination. Grant was a man whose rise from obscurity made him a hero to millions who could see themselves in him. An ordinary man who faced and met extraordinary challenges, his successes and failures seemed to encapsulate the national character. He was so popular with the American public that, despite his two scandal-ridden terms as president, he was nearly nominated to run for a third term.

As a general, he had fought to preserve the Union. As president, he helped to oversee the transformation from union to nation. As a former president, he was the embodiment of the very idea of national union, and of America's entry onto the world stage. As a dying general, he was the symbol of the nation's greatest and most traumatic war. The story of Ulysses S. Grant's life, from his first days on the Ohio frontier to his last days out-writing death in the Adirondacks, is an endlessly fascinating one. Few public figures have ever held a such a firm grip on the American popular imagination. Grant was a man whose rise from obscurity made him a hero to millions who could see themselves in him. An ordinary man who faced and met extraordinary challenges, his successes and failures seemed to encapsulate the national character. He was so popular with the American public that, despite his two scandal-ridden terms as president, he was nearly nominated to run for a third term.

Jimmy Carter ran for president on a wave of post-Watergate disaffection with Washington politics. But inexperience, inflation, recession, and the Iran hostage crisis, derailed his presidency dramatically. His crowning achievement, the Camp David Accords, created a framework for Middle East peace, inspiring his life since. The film traces his ascent from Plains, Georgia, to the Oval Office and explores the role of religion in his career. This is the first of two parts.

Now known internationally as the world's first "gay hometown," San Francisco's Castro District was a quiet, working-class neighborhood of European immigrants only a few decades ago. In this documentary, the story of the Castro's transformation is told by those who lived it, young and old, straight and gay. It's a tale of social upheaval, exuberant street culture, political assassination, and the inspiring coming-of-age of an entire community an ongoing saga even today.