Inside a small adobe home in a remote Peruvian mountain town, with one bed for a family of six and about 70 guinea pigs roaming the floor, Nick Dykstra, a senior at Seattle's exclusive Lakeside School, knew he wasn't in the land of privileged American teenagers anymore.

"They eat the guinea pigs," he said. "It's a steady source of protein for them."

For Chaz Humphries, the moment of recognition came as she prepared to climb with a local basket weaver to a woods where he would cut cane for his vanishing craft.

"I'm wearing my hiking boots, my snap-off pants, my water bottle. I've got my snack packs," she recalled. "He was wearing sandals, a hat, one tool on his back. I'm like, where's your water bottle? Where's your snack packs?"

Travel is famous for broadening perspectives, and American high schools and universities have long offered cultural exchanges to expose their innocents to the world.

Lakeside has a more ambitious purpose.

In launching a global-citizenship program this year, sending the first of what it projects will be 136 students annually for monthlong stays in the developing world, the school hopes to inspire a new generation of world leaders.

"These are students who've been blessed with good minds and material comforts. Now we're asking them, what are you going to do with those?" said Bernie Noe, head of Lakeside School.

Lakeside is perhaps best-known as the school where Microsoft founders Bill Gates and Paul Allen first deconstructed a computer. Since 1923, it has been educating the children of Seattle's business elite. The North Seattle campus, with its rolling lawn, red-brick architecture and steepled administration building, owes more to an idealized New England than to the nearby suburban sprawl.

As the city's law offices and executive suites have become more ethnically diverse, so too has Lakeside. Minorities now make up 34 percent of the student body. But with an annual tuition of $20,500, Lakeside has remained largely a place of economic privilege.

Two years ago at an all-school retreat, school leaders decided that to adequately prepare students for a world that was increasingly global in its concerns, they needed to study and work with a broader range of cultures and people. But they also realized that the school itself had to look more like the world.

"If we want to embrace the diversity of the world, we need to make our own community reflect that diversity," Noe said. "The world is changing, and we need to change with it."

Over the next 10 years, Lakeside plans to offer significant financial aid to as many as one-third of its 750 students, while maintaining its emphasis on academic excellence. Opportunities such as the global travel, which this year cost participants $1,200 each, will be available to all students.

The students who participated in the Peru trip reflect the school's growing diversity. Humphries attended Aki Kurose Middle School in Seattle before enrolling at Lakeside. Her father manages the Montlake Community Center.

Dykstra attended the private Villa Academy in Seattle's Laurelhurst neighborhood. His father is vice president of a pharmaceutical-research company.

Humphries had never traveled outside the country. Dykstra had been to Europe with his family.

In Peru, they said, they were equally overwhelmed by an utterly foreign culture and grateful to the people of Ollantaytambo for patiently explaining their world.

Dykstra had taken four years of Spanish, as well as Latin American literature and history in preparation for the trip, but he said he was at a loss to talk with villagers about the project he hoped to work on: expanding goat paths between nearby Incan ruins as a way to attract more tourists.

Humphries worked with the basket weaver on ways the craft might be made economically viable again.

"We know some of these projects are going to take hold," said Vicki Weeks, a Lakeside alumna and the school's global-programs director, who went along on the Peru trip. "This has been, by far, the most rewarding thing I've done as an educator."

Lakeside isn't alone among private schools in seeing global service as an important component of a contemporary education, said Myra McGovern, spokeswoman for the National Association of Independent Schools.

The association, based in Washington, D.C., represents 1,200 schools.

Within the past two years, she said, many schools have added in-depth cultural studies and live-abroad service programs in response to the globalization of politics, economies and environmental problems. But Lakeside has taken the concept further than many schools, McGovern said, by integrating global studies into the curriculum and school mission.

"It's not just something for students to pad the college résumé," she said.

Among local private schools, The Bush School in Seattle and The Evergreen School in Shoreline offer global-awareness programs. This spring, 19 Bush students spent more than two months in either Chile or The Hague, Netherlands.

Students plan the trips, arrange home stays, and select a service project, said Jack McHenry, director of Bush's Upper School.

"This is very much not a tourist experience. They're there to achieve understanding of another culture and another country. This isn't show up at the airport and go," he said.

At The Evergreen School, which enrolls gifted students from preschool through eighth grade, the culminating trip for graduates involves a three-week service-learning project that in the past decade has taken students to Vietnam, China, Peru and Thailand.

"It's a spectacularly life-changing experience," said Carmine "Chick" Chickadel, head of the school's Upper Division. "It's affected students' college course work; it's defined their career choices."

And though Bush and Evergreen have had programs in place for many years, Chickadel said Lakeside's commitment to global service is significant because of its national prominence as Gates' alma mater.

"Lakeside kids have an inside track to change the world," he said.

The Peru trip already has changed students' perspectives.

"I'd been focused on college and creating a stable financial base for the second half of my life," Humphries said. "Now I'm thinking about how what I care about might also be what I do."

Dykstra has been trying to replicate the warmth and openness of his Andean hosts, who invited an American boy into their homes and prepared a feast of beef, chicken and potatoes — food they can afford to eat only a few times a year.

On his morning runs since returning to Seattle, he's greeted everyone he sees.

"It's tough to even get a 'hi,' " he said, "but I'm not giving up."

Lynn Thompson: 425-745-7807 or lthompson@seattletimes.com