In November, when the first members of the Central American migrant caravan arrived in Tijuana, I accompanied a group of five young people—whose names I’ve changed to protect their privacy—from Honduras and Guatemala to the beach. Daniel, 23, was the only one who had managed to salvage a pair of swim shorts along the way. The shorts were the color of cherry Kool-Aid, patterned with oversized hibiscus flowers. He dove in, letting the frigid water wash away the dust, while his friends stayed on the shore, taking selfies and using sticks to scratch ephemeral love proclamations in the sand. “Ana <3 Maykel,” wrote Ana, 21, whose ultimate goal was to join her sisters in Kentucky.

Less than half a mile away, the Pacific Ocean swallowed the fence demarcating the United States–Mexico border. Beyond it, the skyscrapers lining San Diego Bay formed a postcard-perfect backdrop that seemed teasingly close. While a large number of the group they had arrived with—migrants from Honduras, but also other parts of the world—were preparing to seek asylum, these five realized that, although they had left behind poverty and violence in their respective hometowns, they would not qualify, particularly under an increasingly hostile environment. “Maldito muro,” muttered Luis, 22, one of the boys with us that day, when he saw the border. Damned wall.

Daniel, a slender, muscular young man with the brooding manner and self-conscious posture of a Latino James Dean, had grown up in Comayagua, Honduras. Right before joining the group, he had been living in the crime-ridden city of San Pedro Sula, where he had been working in a supermarket. He’d just been laid off when he found out about the people heading north. He has several family members who already live in the United States; he wanted to work there, but wasn’t overly bothered about what kind of job he might get. All he knew was that the exodus offered a relatively safe, and affordable, way to go north.

Luis—affectionately called “Canche,” a Guatemalan slang word for fairer skin—had traveled from Morales, Guatemala, a tropical, semirural town near the Honduran border. He had worked in construction and at a factory that produced corrugated-cardboard packaging since he was 13. His younger sister Juliana, 19, had cleaned houses in Guatemala City, five hours away.

The night before they left, Luis, who had decided he wanted to go north, asked Juliana to go with him. She called their father, who said he didn’t want her to go; if anything happened to her, it would be his fault. But Juliana, tired of being underpaid and poorly treated for work she didn’t like, had already made up her mind. She was packing her backpack when her father called her back. He was worried, he said, but wished her well.

On her left hand she wore a class ring. Her first goal, growing up, had been to finish secondary school, in a country where the enrollment rate for seventh grade is less than 40 percent. Arriving in the United States was her next one.

Little has been written about how empowering the migrant exodus, at least in its first few weeks, actually was. The adrenaline that comes with taking control of one’s life—along with Daddy Yankee’s reggaetón hit Dura—carried the migrants along, even after weeks of 4 am starts. But by the time the group hit Tijuana, that energy had disappeared. A small but vitriolic group of Mexicans gathered outside the shelter provided for the migrants, protesting and calling them pigs. That Sunday, American border protection shot tear gas at a relatively peaceful crowd of Central Americans as they approached the San Ysidro border crossing.

Meanwhile, Mexico’s National Employment Service held a job fair, offering people humanitarian visas if they could get a job. Daniel’s family, who wanted to hire a coyote to bring him across, told him to stay in Tijuana for the moment; it was too risky. After the job fair, he left, with a larger group from the exodus, for Primo Tapia, a relatively quiet, rustic beach resort less than an hour’s drive south of Tijuana. There, he helped clean beaches for 350 pesos a day, about US $17, or the average daily wage for workers in Mexico.

Juliana, Luis, and Ana stayed in Tijuana. Unable to find space in any of the shelters offered by the city, they slept on the street. Three weeks after they arrived, they had gathered enough money to pay someone to drive them to the border. Just before midnight, they jumped into the United States, where they made their way to a highway. Muddy, cold, and wet, they hid in the dark, waiting for a contact to pick them up.

In the meantime, Juliana tried calling her aunt in Virginia, but she didn’t know that it was 3:30 am on the East Coast, and that her aunt was asleep. There were no buildings nearby; all she could make out was a nearby sign with the strange words “Yield to Horses.”

The United States was bigger than they had realized. Waking up in San Diego the next day, they soon realized the vastness of the country; Guatemala is only the size of Tennessee, and Honduras is the size of Virginia. Because they didn’t have identification, they couldn’t get on a plane, a train, or even a bus to go anywhere.

In the end, their families hired coyotes to take them. Ana left first, to Kentucky. A day later, someone came to pick up Luis and Juliana. The cost was $2,000 per person—$4,000 in total—to get to the other side of the country, where their aunt and cousins, all US citizens, live. In Houston, they had to wait an extra six days while their aunt scraped together the last payment of $500. But the week before Christmas, they finally made it to their aunt’s suburban one-story home, just over two months since they had left home in Central America.

According to the Migration Policy Institute, there are currently 11 million people who are living in the United States without authorization, down from a peak of 12 million in 2007. This number includes 317, 000 Hondurans and 704,000 Guatemalans.

With or without authorization, moving to the United States is difficult. A bank account, a phone, an address, a Social Security number, a credit rating; all of these have to be set up, and some are easier to get done than others.

Most foreigners will use their passport when setting up any of these; Luis and Juliana don’t have identification. Cities like San Francisco and New York offer identification cards available to all residents, regardless of immigration status; even if they made it to these cities, they would still need to show some sort of foreign ID, like a passport, a driver’s license, or a birth certificate. It is very hard to exist when you don’t have a paper trail proving it.

Then there’s the matter of getting a job: the main purpose Luis and Juliana moved to the United States. Luis wants to work in construction; Juliana, who has previously helped her father, a pastor, build their local church, wants to do the same. Luis knows you don’t necessarily need papeles (papers) to work in construction. Even so, he’d be happier if he could get his hands on a Social Security number, somehow—even though he doesn’t know how, or where (not that is necessarily an impediment: IRS data from 2015 report that 4.4 million workers without Social Security numbers filed their taxes).

Earlier this month, over 160 countries met in Morocco to formally adopt the United Nations’ Global Compact for Safe, Orderly and Regular Migration, a “non-legally binding, cooperative framework,” in the United Nations’ own words. Countries including the United States, Australia, Hungary, Switzerland, the Czech Republic, and Austria declined to sign the compact. Austria feared it would lead to “a human right to migration.”

Nationalist politicians are scared because the human instinct to move is as deep, if not deeper, than any inclination to wall ourselves off. If our anatomical ancestors have been around for 200,000 years and we stopped being nomadic nearly 10,000 years ago, then humans have been sedentary for only 5 percent of our history on earth. It is mostly over the last 70 years that migration has evolved into a battle of bureaucratic capitalism: an organizational system of borders, passports, visas, and other exclusionary policies, designed to control the flow of those who have money, and those who don’t.

The night before they reached Tijuana, Ana and Juliana allowed themselves to dream. Ana said that with the money she hoped to make in the United States, she might afford a house for her family. One with a room for her parents, a room for her and her future husband, and another room for her kids; a fence; and maybe—giving herself permission to fantasize a little bit more—a pool. Juliana said she, too, wanted a home for her parents. The girls ricocheted ideas off each other, adding features to their imaginary building plans, until they finally drifted off to sleep.