"As Yosemite Park Turns 150, Charms And Challenges Endure"

"Yosemite National Park, in California's Sierra Nevada, is celebrating the 150th anniversary of the law that preserved it — and planted the seeds for the National Park system. At the same time, the park faces the challenge of protecting the natural wonders from their own popularity.

Since President Abraham Lincoln signed the 1864 law that protected this land, visitors have been enjoying the park's spectacular features, from Half Dome to the giant sequoia grove — and the moonbow at Yosemite Falls.

The moonbow is like a rainbow, but at night. Some photographers time their visits to the park so they can catch a glimpse of this rare phenomenon, which is only visible when the moonlight catches the mist at the waterfall."

Sasha Khokha reports for NPR June 28, 2014.