As you zoom in on a map, from country to region to state to city to neighborhood, somehow more, rather than less, appears. Dimensions and edges and corners reveal themselves, and the expanse of what you’ll never quite grasp makes itself clear yet again. Planning for a trip is an exercise in this realization that there is too much space, too many layers, never enough time: one article leads to another, one destination to another, and then you realize you have a month rather than a few days on your hands. At least. But still, these research endeavors do reveal things, and that is how we came to drive from Mexico City, up over and through Iztaccíhuatl and Popocatépetl National Park, to Puebla. As…