The "Einheitssirene 1957" or short "E57" is a very common and famous civil defense siren in Germany. It was designed during the Cold War to warn people from attacks of the Warsaw Pact as well as fire, storms, chemical and nuclear catastrophes.
During the 1990s many sirens were removed or left unmaintained. Since the 2000s an increasing number of old E57s are either put to work again or replaced with newer systems as they again serve as a part of the German civil defense.
On 10th September 2020 Germany held its first "Warntag" (warning day) in about 30 years. At 11 AM every siren in Germany was activated to test the civil defense system.
I will add a picture of the print tomorrow!
Further information:
Technical Details of the E57:
http://wiki.ig-wasi.de/sirenen/elektromechanisch/e57 (German, lots of pictures)
Civil Defense Sirens (including an E57 audio sample):
https://en.wikipedia.org/wiki/Civil_defense_siren
Warntag 2020:
https://warnung-der-bevoelkerung.de/en/ (English, also: German and French)
JuBe95
