And there are just 15 years to accomplish them. Here's a rundown of the 17 aims, which include ending poverty, hunger and AIDS, fixing the environment and giving everyone access to green space.
Francis will spend several days in the island nation, where he will visit President Raul Castro. In the U.S., the pontiff will meet with President Obama and address Congress and the United Nations.
The U.N. refugee agency has received less than half the $4.5 billion needed to help Syrians who have fled to neighboring countries. As conditions worsen, many are opting to risk the journey to Europe.
Tiny island nations, Latin American developing countries and even non-joiners like Switzerland have all found more power and influence in climate negotiations after forming or joining a group.
"Enough is enough," U.N. chief Ban Ki-moon says, accepting Babacar Gaye's resignation after peacekeepers were accused of raping a girl and killing two people in the Central African Republic.
Minister of Environment, Water and Climate Oppah Muchinguri wants Palmer to face justice in Zimbabwe, wire services report. U.S. authorities are investigating whether any American laws were broken.
The agreement includes a crafty U.N. route to reimpose sanctions — but the U.S. and its allies would have to use the move carefully, because it could release Iran from limits on its nuclear program.
The Millennium Development Goals, set in 2000, revolutionized the fight against poverty. Now the world is setting Sustainable Development Goals. But critics say there may be too many priorities.
The United Nations says there are nearly 60 million refugees around the world. NPR's Scott Simon reflects on what it means to be a refugee, from the lives they leave behind to the struggles they face.