To promote World Peace Day, 21st September, 2015 www.peaceoneday.org Burger King US called for a ‘burger wars ceasefire’ with their long standing rival McDonald’s.

Via full-page open letters in The New York Times and The Chicago Tribune, and out of home billboards. Burger King proposed the two restaurants set aside their differences. To join forces to cook and serve the ‘McWhopper’ – a peace-loving burger that combined all the tastiest ingredients from the McDonald’s Big Mac and Burger King’s iconic Whopper.

The letter extended a friendly, no-strings invitation to McDonald’s to participate in the project, and invited them to visit www.mcwhopper.com to view the full Burger King peace proposal and everything from packaging suggestions to recipe ideas.

The public immediately embraced the campaign and within hours thousands upon thousands of DIY McWhoppers have been made around the world and shared via social media and global news broadcasts. Instantly making the McWhopper a reality.

This resulted in one of the most talked about advertising campaigns of 2015, delivering over US$100 million worth of free media in the U.S alone. Every media story and social media post further raised awareness of the forthcoming World Peace Day.

Whilst McDonald’s decided not to accept the invitation to join forces for the McWhopper project, we were overwhelmed by the response from other QSR brands across the globe. Denny’s, Wayback Burgers, Krystal, and Brazilian chain Giraffas all put their hands up to take part. We accepted these offers and created the ‘Peace Day Burger’, a hybrid burger available for one day only, World Peace Day and would go on to become the 2nd most talked about burger of the year.