Would you endure intense physical challenges and privations, extreme temperatures, dizzying heights, hunger and loneliness …. just for the thrill of it? What kinds of people thrive in hostile environments? It takes a special type of person to embark on extreme adventures and sports. It's not just about your fitness and bodily constitution, you mental and emotional strengths can be even more important. What drives people to the depths and edges of the known world, and how do they survive it? And are there lessons the rest of us can learn from them?