Nearly 300 historians, including some Pulitzer Prize winners, are urging Pennsylvania officials to prevent a casino from being built within a half-mile of Gettysburg National Military Park.

Greetings from the visitor center at Scotts Bluff National Monument in western Nebraska. It is Wednesday afternoon and outside it is hot and windy. The monument is a few miles outside the town of Scottsbluff, where we spent last night in the municipal campground.

Yellowstone National Park rangers on Wednesday put down a female black bear that had come to rely on humans for food.

Here is the list of all 392 NPS units. How many have you visited? Start counting, and let us know.