Eden: Untamed Planet

Borneo is the richest rainforest island of all, home to 60,000 species of plants and animals. Six thousand of them are unique, and more are discovered almost daily. But this 'paradise' is an illusion, the lush forest is effectively growing on a desert, with the soil shallow and poor in nutrients, having been leeched by eons of incessant rain.

The Namib Desert is one of the oldest deserts in the world, having given rise to more indigenous species than any other.

At the very end of east Africa's Great Rift Valley, there's a 'land that time forgot' - the rolling grasslands of the Luangwa Valley. As we travel through the seasons, we find the secret to this Eden's great riches - the annual flood of the mighty Luangwa River.

How the Galapagos became one of the most important areas of biodiversity in the world, with almost 2,000 unique species, including 97% of its reptiles and mammals.

At the far tip of South America lies a magical realm that seems frozen in time: Patagonia, known as 'the end of the world'.

In southeast Alaska, there's an ice-bound Eden that harbours possibly the richest temperate rainforests of all.