One minute it was there, the next it was gone. The collapse of "Wall Arch" at Arches National Park proves once again that gravity does work, even though you might wonder after gazing at the "rockitecture" of this dazzling Utah park.

Our national parks are places of incredible beauty and rich history. But they also are under siege. Across the National Park System, the landscape is being invaded by non-native species that are not just out of place, when you consider what should be growing, but in some cases are actually driving out the natives.

As energy prices creep steadily higher, there's a growing segment of America that believes short-term relief can literally be tapped from fossil-fuel resources in the Western states. But many of those resources are found on public lands that buffer national parks, national wildlife refuges, and wilderness areas, and their development could have dire consequences for those landscapes.

We love our cars, we love our parks, and we love to drive our cars in the parks. Well, at least when the traffic isn’t too bad, and we really don’t mind just going along for the ride. The windshield touring season is nearly here, so it’s time to start thinking about park trips. All of the national parkways are recommended. Here are a dozen other traverses, loops, and shuttles that belong on your short list.

A Utah boy and his family spent Earth Day at Everglades National Park thanks to his winning entry in the National Park Foundation's 2008 essay contest.

How would you describe Arches National Park to someone who had never been to the Southwest? You could try to explain the landscape by comparing it to the old Flintstones cartoons, but what if they weren't familiar with the Flintstones? Do you think they'd believe you if you said Arches was a cathedral of rocks, where gravity doesn't always work, where the sunsets stain the cliffs?