UNITED NATIONS (AP) — It’s not a great moment in world affairs right now. The world is fragmented. Conflicts and crises are raging. It’s against this backdrop that world leaders are attending this week’s annual U.N. gathering. Antonio Guterres, the head of the United Nations, is challenging them to work together not just on all the problems but on modernizing international institutions to prepare for the future. Guterres is leading a “Summit of the Future” over the next couple days to tackle that. The U.N. chief told reporters last week that international challenges are many and varied and are moving faster than our ability to solve them.