Mexican federal police in riot gear block the highway to keep a thousands-strong caravan of Central American migrants from advancing on their way to the U.S. border, outside Arriaga, Mexico, Saturday, Oct. 27, 2018. Hundreds of Mexican federal officers carrying plastic shields briefly blocked the caravan of Central American migrants from continuing toward the United States, after several thousand of the migrants turned down the chance to apply for refugee status and obtain a Mexican offer of benefits. (AP Photo/Rebecca Blackwell)