These are the faces of migrants whose trek from Central America to the United States has transfixed the continent since mid-October.As they drew closer to the US border with Mexico, the thousands of mostly Honduran migrants became a symbol of US President Donald Trump’s tough policies on immigration.The migrants moved closer together to try to protect themselves as they feared the police might take action to stop the advance of the caravan. Credits: ReutersFor both the United States and Mexico, the caravan has raised hard questions about how to respond to a seemingly unending procession of migrants who say gang violence has made their countries unliveable.Alkis Konstantinidis: “At dawn, a group of about 400 Salvadorans crossed from Guatemala to Mexico through the Suchiate river. They had been walking for some 20 kilometres when they were surrounded by Mexican police who moved in to detain them. The mood quickly turned tense. Suddenly, a group of men formed a circle within the crowd. On the ground in the middle, a man was embracing a pregnant woman who had passed out, trying to protect her and her child until she was taken away on a stretcher.” Credits: ReutersThe journey, made partly on foot, is punishing. And for those who reach the Mexican border city of Tijuana, the way forward is uncertain. US officials have implemented a system of “metering,” which limits how many can seek asylum in Tijuana.Also Read: UN Conference on Migrants and Refugees Undermined by Last-Minute WithdrawalsImmigrants sit along the border wall as they await apprehension after illegally crossing into the US on August 29, 2018. Credit: Reuters/Adrees LatifSome migrants scramble over the border to avoid a months-long wait, handing themselves in to authorities in the hope they will be released.Once in the cover of a heavy tinted Border Patrol vehicle, the immigrant let go of his emotions and started weeping. Credits: ReutersThe caravan has also created an early test for new Mexican President Andres Manuel Lopez Obrador as he tries to establish a relationship with the Trump administration.Alkis Konstantinidis: “I was standing beside the border wall near the beach in Tijuana when Tony Mauricio Arita and his daughter Andrea Nicole appeared. They moved silently towards a small, newly-dug hole in ground. Arita inspected the hole for a minute or so, and then instructed his daughter to cross. Andrea Nicole kneeled to check the passage and crawled through, filling her colourful clothes and sneakers with mud.” Credits: ReutersMexico, once the prime source of migration to the United States, now has to manage the rising flow of Central American families heading north to its own border. Lopez Obrador, who took office this month, is still weighing a US proposal that would make asylum seekers wait in Mexico as their claims are decided, a process that can take years.Central Americans take part in a march in a street along the city as they take a break from travelling in their caravan during their journey to the US, in Martias Romero, Mexico, April 3, 2018. REUTERS/Henry RomeroThe caravan came on the heels of another group this spring, and it is not likely to be the last. For migrants with few options, traveling in large groups is safer than making the trip alone or paying an illegal people smuggler, known as a “coyote.”Central American migrants, part of a caravan moving through Mexico toward the U.S. border, stand in line to register at a makeshift centre of Mexico’s National Institute of Migration, in Matias Romero, Mexico April 4, 2018. REUTERS/Henry Romero(Reuters)