There is always something sad about the last night of these trips. They consume you for weeks, they move you around—without sleep—for days. You stay in beautiful places, see strange things, meet famous people, and develop an intense camaraderie with the people you are with. But I felt like it was impossible to explain these things to people back home—my wife, my parents, my old friends. It was like you inhabited two parallel lives—one that made you who you were, and the other that was consuming that person, and transforming you into someone else.