Stepping into the void - would you dare?

"I must have torrents, rocks, pines, dead forests, mountains, rugged paths to go up and down, precipices beside me to frighten me," wrote Jean-Jacques Rousseau of his love of rambling in the French Alps. "The odd thing about my liking for precipitous places is that they make me giddy, and I enjoy this giddiness greatly, provided I am safely placed.