As big as Yellowstone National Park is -- 63 miles north to south and 54 miles east to west -- perhaps it's not too surprising that someone not interested in driving to a trailhead in the park decided to make their own on the edge of the park. But by this fall, that trail should be erased as park crews finish the second of two years' work in removing signs of the illegal trail.

Despite advances made into the 21st century, some of the most striking posters promoting the national parks are those produced shortly before World War II by the Works Progress Administration. The artistry that went into these silk-screened promotions remains as striking today as it was 75 years ago. And if you find yourself in Washington, D.C., in the coming months, you can understand why with a visit to the Interior Department to see a collection of the posters.

In this age of informational instant gratification, how has your national park experience changed? For Millennials, who grew up with smartphones, texting, and Facebook, not so much. For Baby Boomers, who learned to read with actual newspapers, books, and magazines in their hands, whose phones were attached to the wall by a cord, a great deal. Is that change for the good, or the bad?

Mountain goats are spectacular animals, even iconic in places such as Glacier National Park, but they can cause problems in parks where they don't belong. At Olympic National Park, where a 1920s era introduction project brought non-native goats into the landscape, officials are embarking on a management plan for how to deal with the animals. Adding weight to the need for such a plan was the fatal goring of a hiker in the park four years ago.