(Reuters) - The images were dramatic: Central American migrants moving northward en masse through Mexico - men, women and children walking up to 30 miles a day, some hitching rides or catching freight trains.

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The caravans of 2018 and early 2019 were not the first of their kind – but they were, all told, the largest and most visible, gaining attention and size partly because U.S. President Donald Trump repeatedly warned of their approach.

The first major wave started small in spring 2018, in southern Mexico, as migrants on separate journeys gradually coalesced, seeking safety in numbers and guidance from a nonprofit group on the route. Within days, hundreds became more than a thousand. Filthy, dehydrated and exhausted, they arrived in Oaxaca state, spilling into a tiny town square where they paused to rest.

Only a fraction of them that spring made it the rest of the way. A couple hundred migrants crossed the border near Tijuana to seek asylum.

But the appeal of caravans grew as word spread about them through Central American neighborhoods, social media and WhatsApp. In October, a group formed in Honduras ballooned to 7,000 or more by the time it reached southern Mexico, its numbers boosted by TV coverage. Participants called it “the exodus.” Trump called it an “invasion” – a term that would resonate before and after the U.S. mid-term elections.

“Many Gang Members and some very bad people are mixed into the Caravan heading to our Southern Border,” he tweeted in October. “Please go back, you will not be admitted into the United States unless you go through the legal process. This is an invasion of our Country and our Military is waiting for you!”

Where Trump and many of his supporters saw a security threat, many migrant advocates saw a humanitarian crisis, the result of violence, persecution and poverty in migrants’ homelands.

The caravans poured fuel on the fierce political debate over which, and how many, immigrants ought to be allowed into the United States. That debate has only escalated in the run-up to the 2020 elections, as Trump seeks to keep his core promise to literally wall off the border to migrants.

But in the months since the largest caravans reached the U.S. border and dispersed, public attention has mostly moved past them and the migrants who took part.

Reuters’ journalists, who followed the caravans on the ground from their inception, continued to keep track of migrants to see where, and how, they ended up. Facing an increasingly complex and shifting constellation of U.S. policies aimed at reducing immigration, many landed in uncertain territory. Many remain there.

Reuters chose to profile six migrants from three Central American countries, based largely on their varying backgrounds – male and female, young and older, gay and straight. Reporters, photographers and videographers followed them though detentions, deportations, family separations and course changes, as well as hopeful, if fragile, beginnings in the United States.

(For an interactive version see tmsnrt.rs/2VssPY7)