Use precise geolocation data and actively scan device characteristics for identification. This is done to store and access ...

Air-raid siren sounds the warning. Air-raid sirens first sounded the warning in London in September 1939. They became an almost daily part of life in the capital a year later during the height of ...

Air raid sirens were placed on the top of tall buildings - often police stations or similar - or on the top of poles if no suitable building could be found. In cities the sirens were powered ...