Letter from the editor: Lines on maps show how our world is changing

When, in the second half of the 19th century, Otto von Bismarck dreamed of an economic empire stretching from western Europe to the eastern Mediterranean, he surveyed a world in which great powers flexed their muscles in something like concentric circles of diminishing influence. It was an age of empire and regional rivalries, in which the further you got from these powers’ capitals, the less you felt of their force.