Many of the world’s nations, but not the United States, gathered on Monday in Spain to tackle the growing gap between rich and poor nations. They will try to drum up trillions of dollars needed to close it. Many countries face escalating debt burdens, declining investments, decreasing international aid and increasing trade barriers. Co-hosts the U.N. and Spain believe the meeting is an opportunity to close the staggering $4 trillion annual financing gap to promote development and bring millions of people out of poverty. More than 70 world leaders are attending. The U.S. pulled out of the process earlier this month.