Park rangers at Great Smoky Mountains National Park received an unexpected hand-written letter with a heart-shaped rock from a former visitor.
Rangers Jessie Snow and Allison Bate, who shared the story on the park's Facebook page, told ABC News they knew "right away this would be a great opportunity to share a larger message on social media."
A young girl named Karina wrote that she had visited Tom Branch Falls, located in Swain County, North Carolina, inside the national park, and "loved it so much" that she kept a small rock as a keepsake.
"I wanted to have a souvenir to come home with me, so I took a rock. I'm sorry, and I want to return it," she wrote, likely not knowing that removing property from a national park is a federal offense.
"It's pretty simple -- anything in the park, stays in the park," Snow explained. "It's shared by all of us and it should stay there."
"We don't get a lot of things mailed back to us, so getting the actual rock returned in the mail was really a unique and special thing that she had done," Snow said. "We thought the social media post would share the message more broadly."
The rangers from the North Carolina park didn't have further information about Karina since the note had no return address, but they did share a response for the unidentified visitor on Facebook.
"We want her to know that she's appreciated and her actions can help other people learn something," Snow said.
The rangers shared their reply to Karina along with photos of the rock in the location it came from, her letter and her drawing.
Bate said sharing Karina's story provides "education for other [11 million] visitors each year that come and can relate to it."
In her two years working at the park, Snow said she hasn't received anything like this in the mail.