The wave of a hand is a simple gesture, often overlooked. Multiply it by 70,000, though, and you can warm the heart of an ailing child, bring a tear to the eye of a nation and create a tradition. Krista Young and Levi Thompson combined to create one such magical moment in Iowa City.

Krista was inspired by images of the new Stead Family Children’s Hospital, which overlooks Kinnick Stadium, home of the Iowa Hawkeyes. “It’s such a great view of the stadium,” she says. “The patients can see everyone in the stands and wave to them.” So, why not have the fans wave back, she thought on a whim. On a second whim, she shared the first with Levi Thompson, who manages a Facebook page called Hawkeye Heaven.

“I thought it was an awesome idea and decided I would push for it,” Levi says. Throughout the summer, he posted photos of the hospital and the view from the top, with a request for fans to turn and wave between the first and second quarters. By the day of the home opener, he says, his posts had earned more than 2 million views “so I had a good feeling it was going to work.” Krista wasn’t quite so sure, especially since the university had not promoted the wave and made no announcement at the end of the first quarter. “I assumed groups here and there might do it.” But she watched “in total amazement” when all 70,000 fans turned toward the hospital, raised their arms and waved to the children.

“The best part is that it was organic,” says Levi, an Air Force veteran. “No one had to tell anyone what to do in the moment.” Levi was besieged with videos from fans waving in the stands and from the families of patients in the hospital as the kids saw the wave, and waved back. “You can hear them saying how amazing it was,” he says. “You can hear in their voices that they were choked up.” He posted them — and choked up voices across the country. “I wouldn’t say I was surprised it happened. But I’m surprised at the level it reached,” he says of ESPN, CBS and the Big Ten Network spreading the story.

At this point, though, Krista and Levi had yet to meet. “When I started getting asked about it, I didn’t even know her name and didn’t know if she wanted her name out there. I had to go back and find out who she was. She said she was glad it worked out, so I started mentioning her.” Both were the special guests in late September of Bruce Herrald, president of the University of Iowa, at the first night game of the season. Levi decided to kick it up a notch by asking fans to turn on their phone flashlights, turn and wave. This time, Krista knew the fans would respond. “You could hear the crowd getting anxious, saying, ‘It’s almost time. Get your phone ready.’ And then it was gorgeous.” The image again spread beyond Iowa City, across the nation.

Patients call it “a wave of hope” and “life-changing.” “I feel kind of silly getting all this attention because it’s a simple idea,” she says. “The fans took hold of it and made it happen.” She’s right on one hand: The success of Krista’s and Levi’s campaign is a testament to the power of social media. But it’s also a reminder of the power of that little voice inside each of us, urging us toward a small act of kindness.