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PHILADELPHIA (CBS) — Burger King made national news with its “Whopper Detour” promotion that offered customers a whopper for a penny when they went within 600 feet of a McDonald’s restaurant. The campaign was so successful that Burger King’s mobile app is now the most downloaded free app in the Apple App Store.

That puts it above the likes of popular apps such as Youtube, Instagram, Facebook Messenger, and Snapchat.

Credit: CBS3

The “Whopper Detour” was relatively easy for guests to navigate. “If a guest is inside one of these geofenced areas and has the new BK App on their device, the app will unlock the Whopper sandwich for a penny promotion,” Burger King said in a statement. “Once the 1-cent Whopper sandwich order is placed, the user will be ‘detoured’ away from McDonald’s, as the app navigates them to the nearest Burger King restaurant for pick up.”

The 1-cent whoppers promotion will last through Dec. 12 at participating restaurant nations.

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