Growing up in southwestern Minnesota, Karen Nau said a "big trip" was driving to Duluth. Then about 40 years ago she saw an advertisement in the Prior Lake newspaper seeking hosts for foreign exchange students. "When I picked up the phone the next day, it was like a split in my life," Nau said. "My world just opened up." Jean Ann Bjonfald started working with au pairs and their host families 20 years ago. Opening her Bloomington home to young people from Bosnia and China has expanded her family by the hundreds. "I have so many international daughters and sons. And a lot of them are still a part of my life," said Bjonfald, who has walked former au pairs down the aisle and seen their babies baptized. Over Thanksgiving, Bjonfald's family will host 10 people from other countries. "There's always room." And that's the point, they say. By throwing open their homes — and hearts — these Twin Cities women have learned that the best way to expand their world is by welcoming young people from around the globe into it.

Bjonfald's story

Bjonfald started working with Cultural Care Au Pair after her daughter, who was working as a child care consultant for the organization in California, said they needed people in Minnesota. She also thought her mom would be good at it.

"When I started, I worked with two families," Bjonfald said of her work, which has grown to 27 au pairs and 34 families (some of the latter are still waiting to be paired with an au pair).

"A year ago, I had 48," she said. "It's crazy."

According to the U.S. State Department, American host families welcomed more than 20,000 au pairs in 2017. Minnesota families hosted more than 260 of them. "We're proud to say that the majority of those families are part of our program," said Amanda Intelisano, digital marketing specialist for Cultural Care Au Pair.

Au pairs, Bjonfald said, are young people who provide live-in child care to families. They are paid a weekly stipend and are limited to 45 hours of time with the kids per week. They must be provided their own room; many also have use of a family car, although that's not required. For busy families, it's a great source of sanity, she said.

"The parents can actually have a date night again."

Local cultural consultants, Bjonfald said, work directly with the au pairs and their host families, doing everything from giving life advice and mediating disagreements to cooking up a pot of homemade soup for homesick teenagers. Once a month, she gathers her au pairs together for home-baked brownies and outings. Occasionally, when their own host family goes away on vacation or for the holidays, one or more of the au pairs will stay with the Bjonfalds.

"I'm the local go-to," she said.

She's much more than that, including surrogate mom, holiday host, dispenser of ice cream and life advice. Once, when things weren't working between Verena, a 19-year-old au pair from Germany, and her host family, Bjonfald and her husband, Dennis, housed her for a couple of months until they found a new host family. Dennis noticed dark circles under Verena's eyes.

"He asked, 'Do you need a hug?' " Bjonfald said. "She did."

More often than not, though, the time au pairs spend with their host families are happy and culturally enriching for all involved, Bjonfald said. In the past few years, she's even worked with a handful of male au pairs, although the field is still predominantly female.

"They're such lovely girls and guys," she said.

The feeling is mutual, said Claudia Reinan, a former au pair from Germany who came here in 1999, excited about her first trip to the United States but anxious to leave her parents and 4-year-old brother behind.

"At the beginning there was excitement on one hand and sadness on the other," Reinan wrote in an e-mail from Constance, Germany. "Every day was mixed feelings."

The Bjonfalds, she said, helped ease her homesickness.

"At Jean Ann's house, it was family, food & fun!" she wrote. "She wanted us to have a great time, support us in times of troubles and loved to have all different nations with their different attitudes around her."

She added: "I have thought a lot about what made Jean Ann and Dennis who they are. I think it is a kind of openness to new things — always being curious and having a positive attitude when it comes to people."

Their work has led to lifelong connections, such as the daughter of a former au pair who now lives in the Twin Cities becoming their goddaughter. Her name? Jean Ann.

"I love people and I just think everybody has gifts," Bjonfald said, choking up at the gifts she's received from sons and daughters from all over the world. "I think people know that I care."

Nau's story

Until she began hosting exchange students in 1979, Nau had never been out of the United States. Since then, she's been to many of the countries from which her students hail, including Sweden, China, Mexico, France, Germany, Norway, Denmark and Italy. In addition to serving as a host parent over the years, she has been an area representative and coordinator recruiting families and placing teens, first for ASSE International Student Exchange Programs and now for World Heritage, a California-based organization that seeks hosts for foreign exchange students.

To Nau, who has two adult children, that decision to open her home all those years ago "expanded my world."

The key, she said, is to be truly welcoming.

"Of course, you accept them into your home and they become your sons and daughters," she said. "I have been in their weddings. I have been in their homes. When I go, it's like another home for me."

For much of last summer, Nau said, her Prior Lake home was filled with former exchange students who came to spend time with "Mom." She hosted Jonah from Germany last year.

"The world has just shrunk," she said. "I think about our world and how accessible we are to one another. I just think about how great it would be if we took the governments out of there and took the politics out of there and just let the people get along."

Again, that's really the idea — to share, to learn, to see each other as humans first, citizens of elsewhere second, she said.

According to the Institute of International Education, the number of international students enrolled in American high schools more than tripled from 2004 to 2016. More than 70 percent of the 81,981 international students enrolled at U.S. high schools in fall 2016 were here on F-1 visas, which means they're full-time, multi­year students with the intention of earning a U.S. diploma. Less than 30 percent were here on a shorter-term J-1 visa, used mostly for cultural exchanges. About two-thirds of those students come from Europe.

Nau said the secret to making a year with an exchange student work is to "treat them like the woodwork, you know? Not guests." But she admits that a student from Sweden several years ago became the "darling of the place" at a Stillwater over-55 community where the young woman lived.

"She would play the piano when she got home from school. Packed the place," Nau said.

When the young woman went to the airport to return home, she was accompanied by several sobbing residents.

Nau has visited a mosque with Muslim students during Ramadan and taken exchange students to the Mdewakanton community in Shakopee. She's read a gospel passage in German at a wedding in Germany. And, for three months in 2005, she taught English at a university in China. All made possible by her expanded world.

"What have I gained? I've gained friends for life. Children for life," Nau said. "It's made me a citizen of the world, rather than of Minnesota. And it was a fulfillment of something that I had in me that had to come out."

Correction: A previous version of this article misstated the resident of a over-55 community in Stillwater. It was the young student from Sweden.