Thanks to my colleague Scott Klein for telling me that the Peace Sign, one of the most widely known symbols in the world, turns fifty this week. It was first displayed on home-made banners and badges in London on February 21, 1958, to mark the launching of the Campaign for Nuclear Disarmament (CND).

The sign was later appropriated by scores of disparate protest movements, the US counter culture (which made it truly famous) and, because the designer has refused to copyright the symbol, by scores of marketers and advertisers. For reasons unknown the peace sign has resonated like no other and it’s now, at fifty, one of the most widely recognized symbols in the world.

Ironically the symbol itself is a mix of the military semaphore signals N — representing nuclear — and D — representing disarmament (semaphore alphabet). However, Gerald Holtom, a professional artist and conscientious objector during the Second World War who designed the symbol, subverted this use of semaphores by placing the D over the N, the “upside down logo” signifying his anti-military principles.

Watch the video below to see a dramatic, human-lettered peace symbol spelled out in Prague last year. Then, click here to check out a gallery of contemporary versions of the symbol and here for ways you can help wage peace.