After a dismal start, the UN is hosting a "halftime summit" about its 15-year plan to meet a series of human-development targets by 2030. Delegates will try to focus on problems like extreme poverty and gender equality while watching for sparks between the representatives of Ukraine and Russia.

Weeks of emergency sessions at the United Nations have failed to secure a ceasefire in Ukraine, testing the limits of UN diplomacy and putting the credibility of the global body charged with maintaining international peace and security on the line.