In August of 2014, 12-year-old Aubrey Hennig and a few friends were bored and hoping to find a project to keep them occupied during the last week of summer.
The girls decided to open a lemonade stand in their hometown of McHenry, Illinois, and use a portion of the proceeds to a help a child who needed it.
While searching for a recipient on Facebook, the girls found 3-year-old Rowan, a distant relative of Aubrey, who was battling a rare form of leukemia.
"At first, we thought we'd give 15 percent [of the proceeds], then 20 percent, then 50 percent – and then we were just like, 'Let's just give it all,' " Aubrey tells PEOPLE.
Over the next six days, the girls raised over $800 to send to Rowan.
They thought their charitable business venture had come to an end until a shooting rocked their close-knit community.
In October 2014, the father of one of Aubrey's classmates shot and injured two deputies who were responding to a domestic disturbance call.
"I felt really bad for the shooter's daughter and the two deputies and their families, and we wanted to do something for them," Aubrey says. "So I said, 'Hey, remember that lemonade stand we had back in August?' "
The girls held six lemonade stands over four days and raised over $5,000 for all three of the families affected by the shooting.
After seeing the impact their work could have, the girls decided to take their project to the next level. "That's when the lemonade stand became the Lemonade Brigade," Aubrey says.
Courtesy The Lemonade Brigade
"We mentor them so that they can take over the lemonade brigade when we become too old or think that we're too old to be in this," Sammi Parrish, 13, tells PEOPLE.
In June, the girls organized a Worldwide Lemonade Stand to empower more children to help others.
"There were actually 11 children raising money for different people in the community, and even two international [kids] – one in Canada and one in Uganda," Aubrey says. "We just thought it was so amazing."
The Lemonade Brigade's goodwill has touched lives around the globe – from helping Blessing, a little girl in Nigeria, pay for surgery to help her to walk for the first time to fundraising to give Chase, an Illinois boy with cancer, the trip of a lifetime.
Courtesy The Lemonade Brigade
"Aubrey's mom, Chrissy, told me, 'These kids really, really fell in love with Chase and his story and they just want to see him happy,' " Chase's mom, Jen Freund, tells PEOPLE.
In December 2014, the girls held a lemonade stand at a community food and clothing drive and raised over $1,800 for Chase.
Freund says the impact of the Brigade's gesture went beyond the financial donation.
"They just want to be able to make the kids that are going through those things smile," Freund says. "I can't tell you how much they tried to offer us."
Chase was in the hospital the day of the lemonade stand, but his doctors allowed him to be released just in time to meet the girls.
"The kids were totally ecstatic about it," Freund says. "Chase was very, very shy at that point, so he didn’t know what was going on; he didn’t expect all that for him. It was such an amazing experience to watch."
Sheryl Smith Photography / Courtesy The Lemonade Brigade
"Because Chase was so into giving to other kids, we used what was left over to buy Legos and donate them to the children's hospital," Freund tells PEOPLE. "The reason Chase chose Legos was because he knew when you're at the hospital there are never enough of them."
Chase died in January 2015, but his legacy lives on – the girls still cite him as their greatest inspiration.
"For the Lemonade Brigade kids to tell me that Chase was their hero, I'm in awe," Freund says. "Because I'm looking at these kids going, 'They're my little heroes,' you know? They were able to help my son just by wanting to be his friend."
"Chase changed a lot of people's lives," Freund continues. "I've always said I can't be mad and I can't take back what happened, all I can do is know that that was his purpose here. And if his purpose was to change these little kids, or all these people that have helped us just by knowing him and knowing his story, that is incredible to me."
Know a hero? Send suggestions to email@example.com. For more inspiring stories, read the latest issue of PEOPLE magazine