To encourage more businesses to take part in Earth Hour, WWF executed this creative direct mail promotion featuring a custom candle. The yellow candle was placed inside of a box designed to look like a building with all of its lights on. As the candle is removed from the box, the windows of the building go dark.
The WWF reported that thanks to the direct mail promotions they used prior to Earth Hour in 2010, corporate participation increased 260% from the previous year.