As the world convulses in war and contentiousness, its leaders convene at the U.N. to figure it out

World leaders begin convening Monday at one of the most volatile moments in the United Nations' 80-year history, and the challenges they face are as dire as ever if not more so: unyielding wars in Gaza and Ukraine, escalating changes in the U.S. approach to the world, hungry people everywhere and technologies that are advancing faster than the understanding of how to manage them.