The slide projector whirred on the table next to my desk as Mrs. Sampson, our fourth-grade teacher, worked the balky advancement mechanism. She had purchased the Kodachromes in strips from a gift shop during her summer vacation, and the images on the screen transfixed me: vertical cliffs of white granite, waterfalls misting in midair, pine trees rising from a grassy riverbank.

Running more than 160 pages, the National Park Service Management Policies provides park managers with quick reference to how they are to manage their units, what uses are appropriate, and how to usher visitors out of the park when Congress fails to fund the National Park Service. But the Management Policies, which last were updated in 2006, also leave much to interpretation and exception.

The rich cobalt blue waters of Crater Lake are the centerpiece for this national park in southern Oregon. Its geologic birth has left an enormous volcanic caldera, in which the lake rests today. The story of the lake’s birth is as fascinating and striking as the park itself.

Will Crater Lake National Park continue to be such a popular park if its deep blue water wasn't so blue, but perhaps a murkier hue due to algae blooms? That's a question to consider in light of predictions that warming air temperatures will affect both the late's water temperature and water column mixing.