The longest chain of mountains on the planet lies along the western edge of South America like an immense dragon - its tail falling into the freezing Antarctic Ocean, its head breathing fire 5,000 miles north. The Andes, home to the highest points outside the Himalayas, are remarkable not only for their volcanoes and their jagged peaks, the spines of the dragon's back; the niches they shelter are a world of extremes and hidden secrets. NATURE journeys the length of the Andes, passing through deserts and cloud forests, across glaciers and fjords, encountering the amazing creatures that call these habitats home: penguins and hummingbirds, pumas and flamingos, a deer only 12 inches tall, a tree-dwelling bear and much more.