Image taken on April 21, 2011 shows wooden crosses on the border wall between Mexico and the United States in Tijuana city, Mexico. On Jan. 25, 2017, U.S. President Donald Trump signed an executive order for a border wall to be built, but Center for Latin American Monetary Studies (CEMLA) estimated that migration from Mexico has been slowing down since 2008 after growing from 1990 to its peak in 2007. (Xinhua/Guillermo Arias)