A generation of Americans knew just what to do in the event of a nuclear attack—or during a major false alarm, like the one over the weekend in Hawaii. Take cover in a building bearing a yellow fallout shelter symbol.
In 1950, fewer than one-third of the world's people lived in cities. Today more than half do. By 2050, urban areas will be home to some two-thirds of Earth's human population.
As Cape Town suffers its worst drought in a century, residents were warned by the mayor on Tuesday that they face losing piped water to their homes by April 21.