Ban Ki-moon is the eighth Secretary-General of the United Nations. His priorities have been to mobilize world leaders around a set of new global challenges, from climate change and economic upheaval to pandemics and increasing pressures involving food, energy and water. He has sought to be a bridge-builder, to give voice to the world’s poorest and most vulnerable people, and to strengthen the Organization itself. Mr. Ban took office on 1 January 2007. On 21 June 2011, he was unanimously re-elected by the General Assembly and will continue to serve until 31 December 2016.