Car horns warn against natural disasters
In Batman's hometown of Gotham City, a gigantic searchlight projects the Bat signal into the sky in case of disaster to alarm the superhero and the population. In Germany, an extensive network of sirens was used in the past to warn the population against disasters: in case of forest fires, industrial accidents or a looming inundation of a part of town, civil protection agencies could trigger the loud and clear siren alarm, while detailed information was provided by radio and television. However, after the end of the Cold War, most sirens were dismantled in the mid-nineties to be replaced by the satellite-based warning system SatWaS, which informs the population only via radio and television. But if TV and radio are switched off, the warning goes unheard...