Amsterdam-based agency TBWA\Neboko collaborated with Raúl&Rigel, a production company specializing in fabricating unusual billboards, to produce a series of unbranded, blank red and yellow billboards with a hidden compartment to store fries. An internal heat and ventilation system intensified the smell of the snack and directed it toward anyone walking within five meters of the display.
— Read more in McDonald's Made Scented Billboards That Smell Like Its French Fries at AdWeek.