About 1,500 migrants formed a new caravan Wednesday in southern Mexico, hoping to walk or catch rides to the U.S. border. The migrants are mainly from Central and South America. Some say they are hoping to reach the United States before Donald Trump’s inauguration in January, saying they think it might be more difficult after that. They started out walking from the city of Tapachula, near the border with Guatemala, where thousands of migrants are stranded because they do not have permission to cross further into Mexico.