It’s been three years now since 10-year-old Christian Bucks thought his family was moving to Germany for his dad’s job and his mom showed him brochures about his potential new schools.

He would be the new kid there. The one without anyone to play with in the schoolyard. He was just in first grade then, but he knew what loneliness on the playground looked like. He’d seen it at his own elementary school in York, Pa.

But one German school he and his mom looked at had a solution for this. It was called the buddy bench, and if a child was sitting on it alone, it was a signal to the other kids to ask him or her to play.

Christian’s family never did move to Germany, but the little boy is credited with introducing buddy benches to America.

He brought the idea to his principal, Matthew Miller, and the two immediately set out to install a buddy bench at Roundtown Elementary.

Their project was covered by the local newspaper and went viral. Since then, the two have been featured in national news and gave a joint TedTalk in February 2014. Christian has been invited to schools as far away as Los Angeles and Honolulu to help them unveil their own buddy benches. There are an estimated 2,000 schools with benches across the United States now and in about a dozen other countries, Miller said.

“I didn’t like to see kids lonely at recess when everyone is just playing with their friends,” Christian said in a phone interview.

Christian’s mom, Alyson Bucks, said her son had always been empathetic. “He’s always looking out for the person who might need a little help,” she said.

For a kid with no one to play with, there may be no lonelier place than the school playground. And kids with an established group of friends may not think to seek out those who feel excluded.

Loneliness among young children is very common. One 2004 study in London found 80 percent of the kids between 8 and 10 years who were interviewed described being lonely at some point at school.

And it’s also common for children to go off by themselves when they’re feeling sad, and what they really need is for someone to notice. The benches give children a safe, nonjudgmental place to retreat. Once a child is asked off the bench to come play, the hope is that they’ll have the confidence to go play with their new friends again the next day.

Emails poured in from all over the country when Christian’s buddy bench story was picked up by the “Today Show” and the Huffington Post in late 2013.

One second-grader from Los Angeles wrote to Miller, “I have had a hard time making friends on the playground so I am going to use a buddy bench at our school.” Like Christian, he met with his principal and his school installed one. Christian and his mom flew across the country for its unveiling.

Only a week or so after Christian’s buddy bench story went viral, the mass shooting at Sandy Hook Elementary in Newtown, Conn., happened.

As the principal of an elementary school, Miller was devastated. The buddy bench, and the inspiration it spurred, was a timely uplift.

“It was one little boy’s idea, and it really resonated with people,” Miller said. “It gave me hope at a time when I was feeling really down and out after what happened. And here comes Christian with this idea, and I thought, ‘We’re going to be okay.’ ”

In fact, in February 2014, Christian and Miller visited Newtown where Christian was awarded the Charlotte Bacon Act of Kindness Award, named after one of the little girls who was killed.

There are still new buddy benches popping up on school playgrounds around the globe.

Just a few weeks ago a new elementary school in Saskatoon, Canada, installed two bright green benches on its playground with plaques indicating that them as buddy benches.

“It really helps build a positive school climate,” said Shane Armstrong, Saskatoon’s Willowgrove Elementary School principal. “If kids aren’t sure what to do or what their options are, they can go hang out there. … [Then] other kids can go invite that kid to join them in whatever they are doing.”

For Christian, who, when he’s not changing the world is swimming and playing soccer like any other kid, said he thought the benches would just be something the German school and his own would have.

That’s why when he travels to schools and conferences for buddy bench speeches, he always ends them this way:

“Amazing things happen when you share your hopes and dreams,” he says, “and you may end up helping more people than you can ever imagine.”