Pope Francis heads to the United Nations on Friday to deliver an appeal to world leaders to help the poor, combat climate change and end conflicts that have sent desperate refugees fleeing to Europe. Making his first address to the UN General Assembly, Francis will set the tone for an anti-poverty summit where leaders will adopt ambitious new global development goals for the next 15 years. The Vatican flag will be raised at UN headquarters for the first time to mark the occasion, only the fifth visit by a pope to the world body in its 70-year history.