When artists Jeroen Koolhaas and Dre Urhahn visited the favelas of Rio De Janeiro, they wondered how they could help the wider community. Turns out, the answer was a simple lick of paint.

You may have already seen the neighbourhood-wide artwork that they create, but in this video they explain how their ambitious artworks have brought together communities—along with the barbecues they throw, that is. It's a pretty powerful message: that sometimes, positive social change can stem from the simplest of initiatives. [TED]