Most people see a bucket list as a collection of places to take a photo, see a historic landmark, or enjoy a meal. My list is a little different: a collection of trails where you can completely bury yourself in the pain cave, forget about emails, nearly run out of snacks, and have one of the best days of your life. I built this list from my personal experience, running in over 50 countries around the world, plus writing a book about the Fifty Classic Trails of America.