Go ahead—pick a bucket list, anyone's bucket list. Dump that list over and scattered among the Great Walls, Great Pyramids and Great Barrier Reefs is almost sure to be a certain South American wonder: Machu Picchu.
Before my recent trip, that was exactly the thing—okay, one of the things—that scared me. Everyone wants to go, and more and more are getting there; the visitor count is now approaching 2 million annually, a remarkable figure for a place you can only reach, on the next-to-last leg, b...