Mapuche indigenous people protest against the signing of a production agreement between Argentinian oil company YPF and US Chevron, as they occupy two oil wells in Vaca Muerta, Neuquen province, Argentina on July 16, 2013. Vaca Muerta oilfield is one of the largest non conventional hydrocarbon reserves of the world. AFP PHOTO / NA - LA MAÑANA DE NEUQUEN -FABIAN CEBALLOS (Photo credit should read Fabian Ceballos/AFP/Getty Images)
