Professor Iain Stewart uncovers clues hidden within the New York skyline, the anatomy of American alligators and inside Bolivian silver mines, to reconstruct how North and South America were created. We call these two continents the New World, and in a geological sense they are indeed new worlds, torn from the heart of an ancient supercontinent - the Old World of Pangaea.
Something weird seems to be happening to our weather - it appears to be getting more extreme. In the past few years we have shivered through two record-breaking cold winters and parts of the country have experienced intense droughts and torrential floods. It is a pattern that appears to be playing out across the globe. Hurricane chasers are recording bigger storms and in Texas, record-breaking rain has been followed by record-breaking drought. Horizon follows the scientists who are trying to understand what's been happening to our weather and investigates if these extremes are a taste of what is to come.
They form natural boundaries, dictate how we spread around the planet, create natural defenses, and control our weather. From the World War that began with a gunshot in the Balkans to the feuds of the Appalachians, mountains have also been flashpoints.
Volcanoes have a fearsome reputation. In reality, they are the most important force in the creation of the planet as we know it today. Iain abseils into a lava lake and cave dives in a cenote to show how the heat that fuels volcanoes also drives some of the most fundamental processes on the planet.
Between the blue sky above and the infinite blackness beyond lies a frontier that scientists have only just begun to investigate. In "At the Edge of Space," NOVA takes viewers on a spectacular exploration of the Earth-space boundary that's home to some of nature's most puzzling and alluring phenomena: the shimmering aurora, streaking meteors, and fleeting flashes that shoot upwards from thunderclouds, known as sprites.