Academy Award-winner and U.N. Messenger for Peace Leonardo DiCaprio, along with executives from the National Geographic Channel, welcomed U.N. diplomats, top Hollywood talent, and more to the United Nations Headquarters in New York City on October 20 for a red carpet screening of Before the Flood, DiCaprio's forthcoming documentary about the worsening effects of climate change on global communities and ecosystems. The film, which follows DiCaprio as he travels the world interviewing individuals from every facet of society about the climate, will premiere on 21st Century Fox's National Geographic Channel on Sunday, October 30, at 9/8c in 171 countries and 45 languages.