Just when we thought that high school science class had taught us everything, we learn that citrus fruits actually conduct electricity too. Tropicana, with help from DDB Paris, gives us that elusive science lesson while promoting the natural power of oranges.

Actually consisting of 2,500 oranges, the billboard uses spikes of zinc and copper that react with citric acid to provide an electrical current. It then lights up the intended message of ‘Energie Naturelle’. I’m not exactly sure what that translates to, as I failed high school French too.

[via AdFreak]