This story appears in the January 2014 issue of National Geographic magazine.

Noon in the United Arab Emirates is four in the afternoon in the Philippines, which means that Teresa Cruz’s two older children are supposed to be home from school and back inside the apartment of their aunt, who is raising them. Teresa lives in Dubai, the U.A.E.’s most populous city, 4,300 miles from the Philippines. She’s a 39-year-old sales clerk at a clothing store in one wing of a shining multistory Dubai mall. Her job requires her to straighten clothes, ring up transactions, keep track of receipts, and smile whenever a customer walks in. She’s on her feet six days a week, Fridays off.

So Friday midday is a scheduled time for Teresa to see her 11-year-old daughter and 8-year-old son, and because she’s an overseas worker—one of many millions of adults who have traveled thousands of miles from home to take jobs that allow them to send money back to their families—she does this in the overseas worker’s modern way: She pulls a low, plastic stool up to a computer set into a particleboard desk inside the bedroom she shares with four other people. She logs on to Facebook. She clicks a video-chat button, leans in close, and waits.

The first time I waited with her, Teresa was still in her pajamas and fuzzy-eared slippers at midday. She lives in the bedroom with her husband, Luis, who like Teresa left the Philippines years ago; their two youngest children, a baby and a three-year-old; and whomever the couple has persuaded to babysit while Teresa and Luis are at work. (Names have been changed to shield the family from potential repercussions.) This month it was a young Filipina who had run away from her job as an Emirati family’s ill-treated maid and was now illicitly residing in a metal bunk wedged between the Cruz family mattress and the bedroom door. The baby was teething and cranky, and Teresa shushed him as she clasped him to one hip, her eyes fixed on the computer.

Finally a face materialized on the screen. But it was her sister, the children’s aunt. The kids weren’t home yet, she said. She didn’t know where they were. “Call after dinner,” she said in Tagalog, and signed off.

Teresa’s shoulders sagged. She switched to her daughter’s Facebook page, where she was startled to read, “In a relationship.” She stared at the screen. “Maybe she doesn’t mean it,” Teresa said. Justin Bieber was on her daughter’s likes list, as was the television show Glee. As was a Facebook page with many followers who have one attribute in common: Someone in the family has decided that the only way to accomplish the things a responsible parent is supposed to—pay for schoolbooks, make sure the grandparents have enough to eat, prepare the children for college someday—is to leave family behind and find work a very long way away.

During the weeks I came to know her in Dubai, I saw Teresa lose her composure only once. She was talking about an evening in the Philippines more than a decade ago, when she stood outside her family’s home and saw that every house on the street had Christmas lights, every single one except hers. “For us,” she said, “nothing.” Her face suddenly crumpled, and she began to cry.

“I had heard a lot about ‘Abroad,’ ” Teresa told me. “I had heard that when you were in Abroad, you can buy anything.” Abroad was like a country of its own, the place from which impressive things emanated: gold bracelets, Colgate toothpaste, corned beef in cans. In the municipality where Teresa and her ten siblings grew up, an hour from Manila, houses of stone were made with Abroad money. “Our house was wood and very old,” Teresa said. One monsoon season, in the room where Teresa and her sister slept, a sodden wall collapsed. “Then when it’s Christmastime,” she said, “I was in front of my house. And I said, ‘The first salary, I will buy a Christmas light.’ ”

The first salary was from a local job selling sporty shoes. Teresa, just out of high school, could not afford to replace the house’s wooden walls with sturdier stone. But she could buy a string of colored lights. She nailed them up on her house in the shape of a Christmas tree. “I did it myself,” she said. “And I went out in front, and the light was there, and I said, I can do this.”

That was the night that Teresa decided she was tough enough for Abroad.

Migration for better opportunity is as old as human history, but today it’s likely that more people are living outside their countries of birth than ever before. At every hour of every day masses of people and money are in motion, a global flux as complex and shifting as weather, with nations of fewer resources off-loading their ambitious working poor and relying on the money that comes back in their place. “Remittances” is what economists call these person-to-family transfers, whisked home by electronic banking services or hand-delivered by couriers. Tiny in individual increments, aggregate remittances now constitute massive flows of capital into the world’s developing countries. Of the many places from which this money is sent—the richest countries, where employers are willing to put needy foreigners to work—the United States tops the list.

No other city on Earth, though, packs 21st-century international workers into one showy space quite like Dubai. Arrive in the standard manner, disembarking into the sprawling international airport, and you will pass a hundred remittance workers like Teresa and Luis before you reach the curbside cabstand. The young woman pouring Starbucks espressos is from the Philippines, or maybe Nigeria. The restroom cleaner is from Nepal, or maybe Sudan. The cabdriver, gunning it up the freeway toward downtown Dubai, is from northern Pakistan or Sri Lanka or the southern Indian state of Kerala.

And the mad-looking, postmodernist skyscrapers outside the taxi windows? This building, the one like a massive hatchet blade, or the one that resembles a giant golf ball atop a 20-story pancake stack? All built by foreign laborers—South Asian men primarily, from India, Nepal, Pakistan, and Bangladesh. If it’s daylight, empty buses will be parked in the shade beneath the skeletons of the skyscrapers still under construction. They’re waiting to carry men back at dusk to group-housing units, crowded as prison barracks, where most of them are required to live.

Difficult living conditions for foreign workers can be found everywhere in the world. But everything about Dubai is exaggerated. The city’s modern history starts just over a half century ago, with the discovery of oil in nearby Abu Dhabi, then a separate and independent sheikhdom. The United Arab Emirates was founded in 1971 as a national federation encompassing six of these sheikhdoms—the seventh joined the following year—and since Dubai had comparatively little oil, the city’s royal family used its portion of the country’s new riches to transform the small trading city into a commercial capital to dazzle the world. The famous indoor ski slope is only one wing of a Dubai shopping mall, which is not even the biggest of the city’s many malls; that one contains a three-story aquarium and a full-size ice hockey rink. The tallest building on the planet is in Dubai; Tom Cruise was seen rappelling down its outer wall in one of the Mission: Impossible movies. Nearly everywhere the visitor looks, things are extravagant and new.

And because the men who conceived contemporary Dubai decided that their spectacular city would be assembled and serviced by workers from other countries—there were too few Emiratis to do it, and why would a newly wealthy nation expect its adults to wait tables or pour cement in 120-degree-Fahrenheit heat when it could afford to invite outsiders to perform these tasks?—they ended up doing this in exaggerated fashion too. Of the 2.1 million people in Dubai, only about one in ten is Emirati. The rest are the global economy’s loaners, working on temporary contracts with the understanding that they will never be offered Emirati citizenship.

The society they live in, like most of the gulf countries now relying on foreign workers, is as rigidly layered as was 19th-century industrial America, and in many of the same ways: by race, gender, class, country of origin, English-language fluency. In Dubai the professionals and managers are largely Europeans, Americans, Australians, New Zealanders, and Canadians—white people who mostly make too much money to be thought of as remittance workers. Their salaries let them bring over their families, drive Range Rovers, and move into elegant high-rises or landscaped villas. It is remittance workers who cook for them too and look after their children, who clean the streets, staff the shopping malls, fill out the pharmacy prescriptions, run the hockey rink Zambonis, and build the skyscrapers in the scorching sun outside—who make Dubai function, in other words, while sending their wages a long way home.

At its heart, however, this isn’t a story about work and wages and GDP. It’s a love story: about family bonds, colliding duties and loyalties, and the immense barriers to providing for loved ones’ material and emotional needs in a global economy that sometimes seems perfectly structured to pull families apart. Most overseas workers are caught up in love stories of one kind or another, and in Dubai, which has one of the world’s highest concentrations of foreign workers, the Cruzes appreciate the aspect of their daily lives that renders them unusually lucky: They are able to live together, husband and wife, in the same physical place. For a time they were together with all their children, a rare blessing for remittance workers. But the arrival of the fourth baby—the Cruzes are observant Roman Catholics—was more than they could manage. It was Luis, who had been married before and already had one child in the Philippines, who took the older children home. Whenever I asked Teresa about losing physical contact with her daughter and her oldest son, she went expressionless and still. “Very difficult,” she said. And: “I think they have a good family with my sister.” And: “There they will learn to be Filipino.”

Inside the city’s block-long St. Mary’s Catholic Church the Friday afternoon mass is delivered in Tagalog. English masses are at other times of the week, as are the Sinhalese, the French, the Tamil, the Arabic, the Malayalam and Konkani. Those last two are languages of India. One Friday the pews overflowed with parishioners, and standing just outside St. Mary’s doors, alongside others who had arrived too late for a seat, Teresa and Luis kept an eye on their wandering three-year-old while listening to the loudspeaker voice of Tomasito Veneracion, the priest who ministers to the congregation’s Filipinos. He’d recently learned a new word, Father Tom was saying in Tagalog: “gamophobia,” the fear of remaining in a committed relationship.

You must not be gamophobic, Father Tom preached. You must not allow yourself to say that the overseas worker’s family is strong but that you, the actual overseas worker, are weak. Teresa and Luis exchanged glances; the priest was making no direct reference to adultery, but they understood what he meant. Nearly every Filipino in the U.A.E. has friends or relatives in the Philippines and in the gulf who manage long-distance marriages by taking lovers while the remittances flow. “Don’t forget the people you left behind,” Father Tom said. “Don’t forget the reason you’re here.”

In a city of foreign workers these are the stories that predominate: the reasons you’re here, the people you left behind. Frequently they turn out to be one and the same. My daughters, my husband, my parents, and my brother, who is still in the village and who I am now afraid is using drugs. Because I wanted that brother to go to high school. Because although we are eight men in a room meant for four and must soak our filthy work clothes in soapy buckets to remove the smell, the employer pays for my lodgings, leaving me more to send back. Because even though my employer does not pay for my lodgings, I can lower my rent by sharing not only a room but also a bunk, day-shift men and night-shift men taking turns lying down to sleep. Because my wife was pregnant and we were afraid for our baby’s future, and now, by the way, I keep my wife’s picture inside my suitcase, not on the bunkside wall, where the other men in my room might look at her while having private thoughts.

Because this is the way my own father taught me to provide—when he left us, 30 years ago, to quadruple his wages and send the money home.

In Manila there are blocks in which nearly every storefront window is plastered with inducements to leave. KINGDOM OF SAUDI ARABIA, 30 Sandwich Makers. HONG KONG, 150 Domestic Helpers. DUBAI, Play Area Attendant, Vegetable Packers. Tile Setter, Rice Specialist, Janitress (Good Looking), Ice/Fruit Carvers. Job offers luring Filipinos away name destinations all over the world. But the most prominent ads promise work in the Gulf states, especially for the minimally educated.

When Luis was a small boy, his father took just such a job, signing on as a welder in Dubai. He never moved back; Luis senior now returns home only on occasional leave, when he rejoins the woman to whom he is still married—Philippine law does not permit divorce. Luis and his four siblings grew up accustomed to their father’s absence, and they hated it. “We would all take him back to the airport,” Luis told me. “Everybody would have to hug and kiss him. That was the worst part. Everybody would cry.”

Like many nations with persistent poverty, the Philippines has come to depend on these regular departures. A formal acronym is used, often accompanied by praise for heroic sacrifice to nation and family: OFWs, or overseas Filipino workers. A special OFW center takes up part of Manila’s international airport, and multiple public agencies attend to their needs around the country—the Philippines Overseas Employment Administration, for example, and the Overseas Workers Welfare Administration, each with hundreds of employees.

By the time Luis was 22, he was married, with a child of his own, living in the gritty Philippine city in which he had been raised, south of Manila. He worked construction, making four dollars a day. It was enough to survive. But it was not enough to provide, not the way his father had. In Tagalog there’s a phrase, “katas ng Saudi,” that means “the juice extracted from Saudi.” It was the title of a popular 2007 movie about the travails of a Filipino worker returning from Saudi Arabia, and Filipinos still use it to describe the bounty made possible by money from Abroad—the good shoes, the collapse-resistant walls—even when these things are technically katas ng Dubai or katas ng Qatar.

The Cruz family compound, entered through a narrow passageway off a bustling commercial street that borders the water, is now a rich warren of katas ng Saudi: upholstered couches, spacious rooms, a DVD player in a polished bookcase, covered decks overlooking a cousin’s permanent underwater fishnets. Two of Luis’s sisters have gone to college. One is training to become a dentist.

It was Luis senior, studying his son’s circumstances on a home visit and observing that the young man’s first wife appeared to be losing interest in the marriage, who suggested his son find a better-paying job in Dubai. “He knew my situation,” Luis said. “And my mother took me to the recruitment agency.”

Luis still remembers the first sum he sent back to the Philippines, after a few weeks’ work in Dubai: $350, almost three months’ wages under his old rate. He sent money straight to his mother, to support her, his daughter, and his sisters. He found he could earn more by working straight through the week, taking no rest days. His first job involved using a blowtorch in the desert. “You can’t hold your own hat without gloves,” he recalled. “It’s too hot.”

He was desperately lonely. But he was making very good money. He had his father for company. After a while his younger brother Tomas, who was also married, gave up on the Philippines and came to Dubai too, leaving his own wife and a daughter behind.

Still, this is a love story, and it’s sort of a happy one, as remittance-worker chronicles go. While Luis was working in the gulf, Teresa aced the Manila hiring-agency interviews. In Dubai, arriving at the malls to which she was first dispatched, she caught glimpses of hazy outdoor construction sites that helped keep her from feeling sorry for herself. She had air-conditioning at work and during her initial months, two-to-a-room ladies’ housing, a special perk for many new female remittance workers. The dormitory was the nicest sleeping quarters she’d ever had.

She was glad not to be trapped in the lonesome exile of a domestic helper. Filipinas, with their good English and their reputation for kindness and reliability, are in high demand as caretakers, and not just in the Gulf states; nearly half the remittance workers who leave the Philippines are women, often pulled away from their own families by the international demand for nannies, nurses, and assistants for the elderly. But Teresa had heard enough stories about domestics’ lives overseas to know this was not for her. The lucky ones landed humane employers who treated them respectfully, but too often the accounts were grim: no time off, unyielding isolation, verbal abuse from the women in the household, sexual abuse from the men.

Teresa had her own cell phone too—another story often told about domestics is that employers confiscate phones to keep women more attentive and dependent. Every time she went to an exchange house for the gratifying transaction that made her Emirates wages reappear at home as Philippine pesos, she held back enough to buy food and other necessities, and eventually, on a few celebratory occasions, a little gold jewelry.

And because so many Filipinos of both genders wind up working in Dubai, Teresa found compatible friends, young people who, like her, had upgraded from worker dorms to jammed but congenial co-ed apartments. Romance was possible. It was messy romance, to be sure; most of the men were still legally bound to the people on whose behalf they had left.

When Teresa met Luis at a birthday party, he was still married. But he was handsome and tall, with a sweet smile and hair that fell into his eyes, and even though no divorce is permitted at home, there is annulment, for the determined. (When I asked Father Tom how many annulment requests he receives at St. Mary’s, he sighed deeply. “I tell you, this is like a factory,” he said.)

So it was that Teresa, four time zones from home so that her family might have a house that would stand up to rain, married a man who could tell her exactly what it felt like to see his own father only once every two years. But he was adaptable and tough, as was she, and now he has secured work indoors, at the industrial plant where he had been a welder. He likes to cook, which both delights and embarrasses Teresa, since she is not much of a chef herself, and he knows which stores carry pork products, in special alcoves marked off for non-Muslims, as well as green mango and dried shrimp.

At work, moving quietly about the store aisles, Teresa has learned to spot unhappy Filipina domestics, minding other people’s children while their imperious lady employers walk ahead examining clothes. Sometimes, risking much, she makes a whispered approach in Tagalog behind the employer’s back: “Hi, kabayan. Hi, homeland friend.” Are you all right? Is your job so difficult? Why don’t you go home? “They say, ‘I can’t. My family needs.’ ”

Needs what, a less astute listener might wonder, and needs it more than your family needs you? But all remittance workers know that need is complicated and has ways of metastasizing. Food, schooling, medicine, and collapse-resistant walls are things families need; so is pride. The rebuilding of the family house is not a project to be stopped halfway through. A child placed in a costlier school at home will need tuition for years to come; a satisfactorily betrothed daughter or sister will next need money (and likely a dowry, if she is from India) for a proper wedding. In both Dubai and the Philippines I heard laments about spiraling cycles of expectation and dependency, the possessions that materialize as substitutes for the absent parent, the assumption that the overseas worker is a cash dispenser that cannot be unplugged. Once, traveling with friends near Luis’s home in the Philippines, I met an acquaintance of theirs who was on leave from his job in Najran, Saudi Arabia—a sweaty, monotonous restaurant kitchen job, where hardly anybody ever spoke to him except to shout orders. When I asked how it felt to rejoin his wife for a while, he shook his head. “Every week I am here means money is not coming,” he said. “She wants me to go back.”

Journalists and human rights groups periodically document remittance workers’ grievances: unpaid wages, dangerous work sites, wretched living conditions, passports illegally confiscated. But the U.A.E. does not make that documentation easy. Some nongovernmental organizations are banned from working in the country, and the national press treads carefully to avoid offending Emirati officials, who are quick to snuff out any form of organized complaint. The U.A.E.’s defenders point out that it remains among the most welcoming of the Gulf states; women dress as they wish, non-Islamic houses of worship thrive, and the streets are safe for tourists and residents alike.

“All global cities have problems like this,” retired Emirati political science professor Abdulkhaleq Abdulla told me. “All global cities are built on foreign workers and cheap labor. Dubai embodies the best and worst of globalization—the best because this is a very tolerant city, a very liberal and open city. But this city has a lot of misery in it and a lot of poor and a lot of exploitation. So which glasses do you want to wear? Optimistic or pessimistic? I tend to look at it from both sides.”

The U.A.E.’s surest leverage for keeping its contracted workforce compliant is the threat of deportation: Stir up trouble here, ungrateful guest worker, and we will ship you right back to the less lucrative life you left at home. That is true of every labor-importing country in the world, including the United States, and in both Dubai and the Philippines people kept reminding me that remittance workers go abroad because they decide to—because they have weighed carefully their own possibilities, as they understand them, and the ways they might contribute most to the people they love.

Picture this, at the Manila airport: A crowded reception terminal, scores of people just outside customs, all pressing and shoving for a glimpse of the first returning passengers to emerge. This was about 13 years ago, Teresa’s initial visit home after a three-year absence. When she recognized one of her brothers and then another, and then a sister and some nephews, she was startled: Every one of the relatives who’d shrugged her off when she’d left the Philippines had crammed into borrowed cars to welcome her home. Atop the luggage cart she pushed toward them was a hefty cardboard box containing a new color television—a big one. “At home we had a small black and white,” Teresa told me. “But I said, ‘I want to buy a 25-inch TV.’ I saw in their faces how happy they are to have this TV. Even now if there is no one watching, the TV is on.”

The room in which the television stands—the sala, the big family room—has over the years been wholly reinforced. The construction was done bit by bit; Teresa’s parents would tell her about it in long-distance conversations, how every few months a little more of the money Teresa wired was being funneled into repair. First the sala. Then the kitchen. Then the sleeping area, with the old bamboo mats on the floor. “Slowly by slowly,” Teresa said, “they made it stones.”

In Tagalog there’s a popular song about a remittance worker, recorded a quarter century ago by Roel Cortez, called “Napakasakit Kuya Eddie.” Teresa darted to her computer to call up YouTube when I told her I’d never heard it. On the screen appeared the silhouette of a small boat lashed to a buoy in a golden sea.

“I’ll translate,” Teresa said. Music swelled. The lyrics scrolled. “I’m here in the middle of Arab country and working so hard,” Teresa said, as Cortez’s rich voice rose. “In the very hot place … the hand will become hard, and your color become dark.”

She was absorbed, singing and translating, working to catch up in English. “When he sleeps, he is always thinking to become past the time, so that he can go back home,” she said. “And he’s so glad that his son write him a letter, but he become shocked, and his tears come out—‘Dad! You go home, and make it fast! Mommy has another man!’ ”

By the last verse the song’s narrator has returned to the Philippines to find his two children smoking marijuana and his wife having produced a third child, not his. “It’s so difficult, brother Eddie,” Teresa sang loudly, jouncing her own teething baby on her knee. “What happened to my life?”

The baby had quieted, and Teresa passed him up to Luis. The three-year-old was sprawled on the family mattress, drowsily watching cartoons from the Filipino satellite station. In a few years, when they’re too big for that mattress, they’ll go to the Philippines too. The Cruzes possess amazing communication devices that workers of their parents’ generation did not have, of course: cell phones with instant messaging, Facebook, apps of international reach, and the computer near which Teresa and Luis now hovered, waiting, the baby in Luis’s arms.

But on this Friday afternoon, as the Cruzes’ daughter and big son finally appeared in a video window, mashed together on a couch and merrily punching each other in the arm, it seemed to me that it must have been a special comfort to their parents, amid all the laughing and pointing and waving, to have with them in their crowded quarters two small, needy bodies still close enough to embrace.