"It was ten miles to the dam. It was the longest, hardest ten miles I have ever travelled," said Mark, who has hiked to remote areas in Peru and the Amazon rainforest. "It is incredibly difficult country to get through. The foliage is so thick, you can't see very far … then it turns into muskeg, which is incredibly difficult to walk on. And then it goes out to complete bog swamp. "The mosquitoes are absolutely horrific."