You'll be hard-pressed to find a more dynamic setting than at ocean's edge at Hawaii Volcanoes National Park when a river of molten lava is pouring into the Pacific Ocean.

In our continuing series of how to, and how not to, run rivers in the National Park System we bring you this selection from Canyonlands National Park. As you can probably surmise, the chocolaty Colorado River is best enjoyed from atop, not underneath, the raft.

What, you might wonder, is a bear jam in Katmai National Park and Preserve? To understand this phenomenon, listen to this podcast in which Ranger Michael Glore differentiates between jamming bears and a crush of tourists anxious to see brown bears at Brooks Camp.

Hawaii Volcanoes National Park protects and showcases a spectacular volcanic resource. Visit the park and you're able to see lava flows, steam vents, and possibly minor eruptions.

There are more than a handful of national parks that seemingly were dreamed up with thrill-seekers in mind. Black Canyon of the Gunnison National Park is one of them, particularly if you like getting wet.

Running rivers ain't always pretty, as this short video from Big South Fork National River and Recreation Area clearly shows.

Few rigors matched those endured by the men of the U.S. Life-Saving Service. They spent the harshest months of the year in remote coastal locations watching for ships that had run aground. Then, typically when the weather was worst, perhaps in the middle of a storm in the middle of the night, they had to row out to sea through the surf with hopes of saving lives.

If you've ever spent any time fishing, you know how hard it is to reach down and grab a fish with your bare hands. Well, the wolves at Katmai National Park and Preserve in Alaska are pretty gifted when it comes to fishing, as this National Park Service video reveals.

Wildlife biologists in Alaska are concerned about the decline in harbor seal numbers at Glacier Bay National Park. In an ongoing study they are capturing seals to take biological samples and implant transmitters that hopefully will shed some light on why the overall population has been dropping.

If you've ever wondered whether it's worth the trek to Biscayne National Park, watching this video surely will convince you to make the journey.

Northern elephant seals are huge marine animals, with males weighing more than two tons. Point Reyes National Seashore is a great place to view these animals, but not in summer. Rather, come either late or early in the year when the seals congregate on the seashore's beaches to breed and give birth.

Grizzly bears and wolves don't always get along, but as this video footage obtained by USGS researchers in Glacier National Park demonstrates, sometimes they will tolerate each other.

Curious to see what it looks like when a bison tosses a visitor who gets too close in Yellowstone National Park? Check out this video.

Sweltering in another heat wave on the East Coast? Tired of the rain in the Midwest? Fed-up with wildfires in California? If you'd prefer snow, head to Glacier National Park. Check out this video to see how just much snow still remains to be cleared from Glacier's Going-to-the-Sun Road.

Ever wonder what bears do when we're not watching them? This remote USGS footage obtained in Glacier National Park shows how bruins scratch some of their itches.