DOHA, Qatar — So quickly has this high-rise city sprouted from the desert that one of its enduring features is the crawl of seemingly perpetual traffic.

Another? The omnipresence of the expats who are building it.

Qatari men dressed in long white robes and headdresses called ghutra and women covered head to toe in burqa-like black abayas are hard to spot in their own country among the nearly nine out of 10 people here who come from somewhere else.

These hordes of manual laborers largely from India, Pakistan, and other places and professionals mostly from the West are part of a large and growing army of international travelers who don’t just land somewhere and spend a week, but settle in. Many get to see the world not through the windows of a tour bus, but from their own doorsteps, living and working abroad in the ultimate sort of global tourism.

“Every day you’re reminded that you’re on an adventure,’’ said Bailey Snavely, an American who has lived in Doha. Tourists who make brief visits to exotic locales like this, Snavely’s friend and fellow Doha expat Laura Belardinelli pipes in, “get a taste of what a country and a culture have to offer. But when you live it and you breathe it, the good and the bad, it makes you more of a well-rounded and open-minded person.’’

That, along with practical considerations such as high pay, low or nonexistent income taxes, and the ability to build a resumé for a career back home have helped to drive the number of expats worldwide to a record 51 million, according to the market research company Finaccord. The figure is projected to jump to 57 million by next year.

Not all of these are fortunate westerners who, in many foreign destinations, can enjoy good housing, private schools, and cheap domestic help. Many, including in Qatar — which has the world’s largest proportion of expats — work in comparatively harsh and even hazardous conditions, Amnesty International reports, though the government has promised reforms leading up to the 2022 World Cup, which it’s hosting.

Nor is being an expat always easy even for people with advantages. “You have to have a sense of adventure. You have to be willing to take a risk,’’ said Belardinelli, an ardent amateur athlete who, because of religious and dress restrictions, is limited to playing only in women’s leagues in Doha and not with men. “You’re in a completely different culture, especially in the Middle East.’’

But the benefits, for most, outweigh these things. Many expats use their homes abroad as stepping-off places for further travel, for instance.

“Is sitting on the sidelines going to be the determinant of my happiness here? No,’’ said Belardinelli, who works in business financing. “I was just in Santorini, lying on the beach. I can suck up not being able to play in a game with men in Doha.’’

One reason more people are living abroad is that it’s an increasingly important part of a domestic career, said Scott McCain, senior vice president of Paragon Global Resources, which helps settle expats overseas. Others are sampling it in college; the number of Americans studying abroad has more than tripled in the last 20 years, to a record 304,467, according to the Institute of International Education.

“They get it. We’re in a global mind-set now,’’ McCain said. “Any college you go to, they’re going to be in your face about all the study-abroad programs.’’

It’s also easier to live overseas, he said, thanks to technology that makes it cheap and easy to communicate with home. “There isn’t the isolation that there once was. You’re going to be as well connected as if you were in New York City.’’

Growing demand is yet another reason more people are making these kinds of choices. Teachers in particular are increasingly sought after. One placement company, International School Services, is trying to fill 1,400 overseas teaching jobs, Laura Light, director of education staffing, said.

“Just Google ‘working abroad’ and you find all kinds of options,’’ said Light, who has herself worked in Kuwait, Singapore, the Dominican Republic, El Salvador, and England. “It’s an incredibly mind-opening experience for people who have a sense of adventure — who want to go find out about the world.’’

Not every expat is motivated by these things. Tracy Slater, who grew up in West Newton, ended up living in the Tokyo suburbs after marrying a Japanese graduate student who she met when he attended Boston University. She’s written a book about her experiences called “The Good Shofu: Finding Love, Self, and Home on the Far Side of the World.’’

“I’m seeing Japan from the inside and the outside at the same time, whereas when you travel you see it just from the outside,’’ Slater said. “There’s a sense of curiosity and valuing a life of learning, not in a self-righteous way, but in terms of discovering new things and finding a way to compensate for the discomfort of living so far away and living in such a different world.’’

Once an instructor at the state prison in Norfolk, where she taught literature and gender studies through BU’s College Behind Bars program, Slater said she’s “always been interested in other worlds.’’ And while living in the Tokyo suburbs, with their shopping malls and fellow parents pushing strollers “is not that fascinating in some ways, in other ways I’m fascinated every day when I walk out the door and see how much the same it is while also being so different. That dichotomy of the commonplace and the different — I’ll never get bored with that. I’ll never lose my sense of wonder in the world.’’

That’s how Megan Reid sees things, too. Reid, who was raised in Dedham, Marion, and Cotuit, among other places, now lives in New Delhi, with her husband, whose job it is to open new locations of the Wendy’s restaurant franchise.

“The most overwhelming thing about being here is the scale of things,’’ Reid said. “There are 25 million people in Delhi, and with that comes their trash, their pollution, the traffic. The strain is enormous and certainly unlike a well-pulled-together city like Boston. . . . But that’s all on a bad day. On a good day this city is magical.’’

Her daughters, Reid said, go to a school with classmates from 55 countries. “Their eyes are wide open to different cultures. They know their Muslims from their Sikhs. They have been swimming with elephants, spotted tigers in forests, and learned to ski in Kashmir. We would not have missed it for the world.’’

And that’s a far cry from what a tourist usually gets to see, as Snavely — who worked as an administrator at Doha’s Education City complex of American, French, and British university satellite campuses — remembers from family trips to Europe.

“We would stay for a week and every time I left I’d feel like it wasn’t long enough,’’ she said. “I started to feel like I’d never be in a place long enough unless I lived there.’’

Jon Marcus can be reached at jon@mysecretboston.com.