200 million years ago North and South America were carved from Pangaea, and pushed westwards as separate island continents. The episode explains how subduction has created the longest continual mountain range in the world - the Andes, and how 300 million years ago New York was at the heart of a huge mountain range. [1] Using llama as an example, Iain explains how most of South America's wildlife originated in North America, and only came south when the two island continents of North and South America joined three million years ago.