"The Edge" tells one of the great stories of humankind - the story of discovering and coming to terms with the ancient, complex and fragile world we live in. Australia's Blue Mountains wilderness is a unique and exquisitely beautiful part of that world. The landscape is inconceivably ancient. When the Grand Canyon in Arizona was a shallow creek, the cliffs and chasms of the Blue Mountains looked much as they do today. The plateau has been carved into a labyrinth of lost worlds - beautiful and treacherous waterfalls, canyons and underground rivers, carved by streams that lead back into the world as it was ninety million years ago. The Blue Mountains wilderness protects itself from the encroachment of modern society with a formidable barrier of thousand metre vertical cliffs.