Trails are meant for walking, but Shenandoah National Park is seeing damage to rare plants and other fragile features.
The damage comes from visitors who don't realize they're trampling remnants of the last Ice Age.
The worst damage has occurred at some of the park's most popular hiking or climbing spots -- including Little Stony Man, Old Rag Mountain and Hawksbill Mountain.
Park officials say it's happening as people walk along cliffside trails to scenic overlooks, or go rock-climbing and distance hiking. But if they're not careful, they stumble across -- and destroy -- rare plants, lichen and rock formations.