Once upon a time, when you turned off Route 1 onto Washington Road, you knew you were approaching a rare and wonderful place. A long avenue flanked on both sides by towering elms, columns of forsythia, and empty fields, it lured you onward. You followed the road over the canal, over Carnegie Lake, and across the stone bridge. Past the elegant boathouse, up the hill, and there you were—in the magical kingdom of Princeton University.