We know that Burger king and McDonald's are two highly competing fast food restaurants.
McDonald's had a fundraising campaign of donating two dollars to cancer affected children for every Big Mac burger that they sell. To support this campaign, Burger King came up with a campaign named 'Day Without Whopper' through which they stopped selling their top selling product Whopper burger for a day. McDonald's had a record breaking sales of Big Macs on that day.
In addition to the removal of Whoppers from sale, Burger king recommended their customers who were disappointed on the unavailability of Whopper for the day, to visit the nearby McDonald's and participate in the good cause by buying a Big Mac instead.
The great initiative by both the companies and the pictures of McDonald's and Burger King shaking hands was trending on Social Media.