The Peace Day Burger is the result of a partnership between Denny's Wayback Burgers, Krystal, Giraffas USA, and Burger King and combines together parts of Denny's Bacon Slamburger, Wayback's Wayback Classic, Krystal's Cheese Krystal, Giraffas' Brutus, and Burger King's Whopper.
If you want one, they're actually offering it free of charge but it's only available at a single pop-up restaurant for one day only in Atlanta. The restaurant is located at 1122 Northside Drive and the Peace Day Burger is available from 11 AM through 6 PM. There will only be 1,500 burgers available on a first come, first served basis.
While the details weren't released, the burger appears to take its top bun from the Wayback Burger, ham from the Brutus, diced onions and a square slider patty from the Cheese Krystal, bacon from the Bacon Slamburger, and a flame-grilled beef patty and bottom bun from the Whopper. There's also lettuce, tomato, ketchup, American cheese, and pickles in the burger.
The Peace Day Burger came about after McDonald's rejected Burger King's offer to collaborate together on a McWhopper to raise awareness for Peace Day. The subsequent buzz led several other burger brands offering to work with Burger King on a mash-up burger and the Peace Day Burger was born.
If you still have your heart set on a McWhopper, you can still make one yourself by buying both a Whopper and a Big Mac and combining various parts of them together.
Had the McWhopper come through, it might have looked something like this:
Images via Burger King.