This episode explores the palaeogeography of Earth over millions of years, and its impact on the development of life on the planet. Tyson starts by explaining that the lignin-rich trees evolved in the Carboniferous era about 300 million ago, then explains on the nature of plate tectonics that would shape the landmasses of the world and the asteroid impact that initiated the Cretaceous–Paleogene extinction event, leaving small mammals as the dominate species on earth. Earth's landmasses are expected to change in the future and postulates what may be the next great extinction event.

The German army launched Operation Barbarossa, the invasion of the East, with supreme confidence in its own superiority. High Command was sure that victory would come as quickly and as easily as in France. At the onset, the troops advanced rapidly and the Panzer forces under General Guderian were unbeatable. There were, however, far more casualties and more wear-and-tear on equipment than anticipated. The invading force got bogged down short of Moscow and the withdrawal from there was a severe psychological blow to the men. When an extremely severe winter set in, morale sank further. The soldiers were not equipped for such low temperatures and their guns and machinery could not cope. Hitler ordered his troops to stand firm.

This is the story of three maps, three 'visions' of London over three centuries. The Morgan Map of 1682 was the first to show the whole of the City of London after the Great Fire of London. In 1746 John Rocque produced at the time the most detailed map ever made of London. Like Morgan's, Rocque's map is all neo-Classical beauty and clinical precision, but the London it represented had become the opposite. In engravings of the time, such as Night, the artist William Hogarth shows a city boiling with vice and corruption. Stephen Walter's contemporary image, The Island, plays with notions of cartographic order and respectability. His extraordinary London map looks at first glance to be just as precise and ordered as his hero Rocque's but, looking closer, it includes 21st century markings such as 'favourite kebab vans' and sites of 'personal heartbreak'.

The series concludes by delving into the world of satirical maps. How did maps take on a new form, not as geographical tools, but as devices for humour, satire or storytelling? Graphic Artist Fred Rose perfectly captured the public mood in 1880 with his General Election maps featuring Gladstone and Disraeli, using the maps to comment upon crucial election issues still familiar to us today. Technology was on the satirist's side with the advent of high-speed printing allowing for larger runs at lower cost. In 1877, when Rose produced his 'Serio Comic Map of Europe at War', maps began to take on a new direction and form, reflecting a changing world. Rose's map exploited these possibilities to the full using a combination of creatures and human figures to represent each European nation. The personification of Russia as a grotesque-looking octopus, extending its tentacles around the surrounding nations, perfectly symbolised the threat the country posed to its neighbours.

Our icy adventure begins with host Dr. Iain Stewart in the Alps, where he goes down an ice crevasse to show viewers how snowfall develops into expansive masses. Then, we see how ice can shape the earth's topography giving rise to features like Yosemite National Park and Manhattan Island, in NY. Finally, journey to Greenland and see how ice sheets and glaciers are melting at a phenomenal rate that is likely to accelerate over the coming years, changing the world as we know it.

Sir David Attenborough journeys to both Polar Regions to investigate what rising temperatures will mean for the people and wildlife that live there and for the rest of the planet. David starts out at the North Pole, standing on sea ice several metres thick, but which scientists predict could be Open Ocean within the next few decades. The Arctic has been warming at twice the global average, so David heads out with a Norwegian team to see what this means for polar bears. He comes face-to-face with a tranquilised female, and discovers that mothers and cubs are going hungry as the sea ice on which they hunt disappears. In Canada, Inuit hunters have seen with their own eyes what scientists have seen from space; the Arctic Ocean has lost 30% of its summer ice cover over the last 30 years. For some, the melting sea ice will allow access to trillions of dollars worth of oil, gas and minerals. For the rest of us, it means the planet will get warmer, as sea ice is important to reflect back the sun's energy. Next David travels to see what's happening to the ice on land: in Greenland, we follow intrepid ice scientists as they study giant waterfalls of meltwater, which are accelerating iceberg calving events, and ultimately leading to a rise in global sea level. Temperatures have also risen in the Antarctic - David returns to glaciers photographed by the Shackleton expedition and reveals a dramatic retreat over the past century. It's not just the ice that is changing - ice-loving adelie penguins are disappearing, and more temperate gentoo penguins are moving in. Finally, we see the first ever images of the largest recent natural event on our planet - the break up of the Wilkins Ice Shelf, an ice sheet the size of Jamaica, which shattered into hundreds of icebergs in 2009.