For those willing to go to the edge, for those who love to run close to the sky, here are some of the world's most challenging and beautiful running trails and races. Twelve trails are covered in depth, and many more are included. From Norway to South Africa, Hong Kong to Colorado, and Switzerland to Columbia, these profiles are accompanied by travel information, as well as stories from those with experience on these trails, whether talking about the music they run to, or the good will shared among fellow runners.