Millions of Americans visit national parks each year. This spring, one of them decided to give back — although it was something she took in the first place. Rangers at Great Smoky Mountains National Forest received a letter from a visitor named Karina, who wrote that “I loved it so much I wanted to have a soiveneir to come home with me, so I took a rock. I’m sorry and I want to return it.” The rock has since been returned to the park. Dana Jacobson reports. Source