The image of our planet with its lights on, made popular during Earth Hour, puts darkness on the endangered list. This view from space shows whole continents bathed in a fluorescent glow and gives the impression that the world is alight day and night. Yet the view on the ground can still be different. Toe-stubbing darkness is alive and well, and moonless gloom is possible to encounter even on the fringes of a city. For those moments – expected or unexpected – it’s a good idea to carry some kind of light.