14 powerful photos that will change how you think about the world today

(CNN)The world's leaders meet Friday at the United Nations Global Assembly in New York to sign the Sustainable Development Goals, an ambitious set of 15-year targets for tackling global poverty, inequality and injustice.

World-famous photographers from countries including Nigeria, South Africa and Brazil have captured startling images of inequality -- to support Action2015's campaign calling for change.
Go through the gallery to see the images and read what the photographers told Action 2015 about what equality means to them and the power of imagery to inspire action.
    Listen to esteemed Nigerian photographer George Osodi explain his photo essay "Trading Places," representing the inequality of his beloved Lagos.