A pair of radical activists drives east, from the West Coast of the US to a quaint skiing town in Colorado. They’ve watched as local environmental groups tried - and failed - to prevent the expansion of a ski resort into pristine forest land. And they’ve had enough. Their plan? To burn the resort down.

This group will go on be named the number one domestic terror threat in the United States. And the green movement is split about whether their actions went too far.

Presenter: Justin Rowlatt