"War is over! If you want it" proclaimed a series of billboards erected around the world by John Lennon and Yoko Ono in December 1969.
It was the start of a long history of Ono using ad space to spread messages of good will, rather than sell cars.
The grand billboard ad has become one of the Japanese artist's key methods of communicating.
Recently, the "War is Over!" posters were recreated in 2005 for the documentary The US Versus John Lennon and Ono has since promoted her "Imagine Peace" initiative using the same method.
She was at it again this weekend when she booked a full page in the New York Times for an "Imagine Peace" message. This followed an anti-fracking ad in the paper ("Imagine there's no fracking") posted by Ono and her son Sean Lennon earlier in December. Ono was also behind a stunning three-minute "Imagine Peace" billboard display in New York City's Times Square.
Ono surely deserves praise not just for her 43-year campaign for peace, but for the equally laudable task of helping newspapers' advertising sales teams fulfil their monthly quotas. Thanks Yoko!