In the shadows of what was once called the “Dark Continent,” a scramble has come and gone. If you heard nothing about it, that was by design. But look hard enough and—north to south, east to west—you’ll find the fruits of that effort: a network of bases, compounds, and other sites whose sum total exceeds the number of nations on the continent. For a military that has stumbled from Iraq to Afghanistan and suffered setbacks from Libya to Syria, it’s a rare can-do triumph. In remote locales, behind fences and beyond the gaze of prying eyes, the US military has built an extensive archipelago of African outposts, transforming the continent, experts say, into a laboratory for a new kind of war.