Not that “Africa” is a country, of course, but it helps to look at broad, continent-wide trends. People are reluctant to the idea of demographics as the great driver of history. In the general case, this might be true. But the 21st century will see an unprecedented situation: one where every continent will face large-scale aging and slowing demographic growth. Every continent, that is, except one: Africa (or, to be more specific, sub-Saharan Africa). Africa is young whereas the rest of the world is graying, and any strategic thinking about the 21st century must take this into account.