Andy Torbet discovers that the Madagascan rainforest-dwelling Darwin's bark spider might be tiny but has a truly epic power - it makes the world's toughest natural fibre and it uses it to make 25-metre-wide webs! To try to match this awesome arachnid, Andy is set the challenge of finding a way to fire a man-made rope to the top of a 30-metre-high building in Norway, before using top technology to help him climb it.