I remember as a kid, back in the 1950's, the air-raid siren on top of our local telephone exchange being tested at regular intervals, usually on a Sunday if memory serves correctly.
We lived some distance away from it, but it was pretty loud.
Of course, fast forward to current times and we now have the National Emergency Alarm or whatever they call it on our mobile phones. When they tested it in the south-west out of the blue last year, it scared the living daylights out of me - I think I finished up vibrating in tune with the wretched phone ......