Los Angeles gave America the modern street gang. Groups like the Crips and MS-13 have spread from coast to coast, and even abroad. But on Southern California's streets they have been vanishing. Has L.A. figured out how to stop the epidemic it set loose on the world?
Germany's national railway company, Deutsche Bahn, plans to test small drones to try to reduce the amount of graffiti being sprayed on its property. The idea is to use airborne infra-red cameras to collect evidence, which could then be used to prosecute vandals who deface property at night. A company spokesman said drones would be