Perhaps it's proof that you're never too young to consider a career in paleontology: A 7-year-old visitor to Badlands National Park earlier this year spied a partially exposed fossil that turned out to be the skull of a 32-million-year-old saber-toothed cat.

Visitors to historic buildings have said many times, "If only these walls could talk…." Perhaps that was the case for employees at Klondike Gold Rush National Historical Park in Skagway, Alaska, when an intriguing discovery was made during restoration of an old building.

A 26-year-old climber who found himself in a perilous position on Teewinot Mountain in Grand Teton National Park resorted to a life-line -- his cellphone -- to summon help, and rangers responded with a helicopter to lift him to safety.

John Muir and President Theodore Roosevelt camp in Yosemite. This four-day trip is reenacted by two great actors.