Much has changed since Lewis and Clark took a hike across the western United States. Among those changes has been an infusion of non-native vegetation that threaten to overrun native vegetation. At Lewis and Clark National Historical Park, researchers are working to wipe out the intruders.

If the recent winter months have you wishing for some time on an island in the South Pacific, here's a unique approach: the Home Stay Program at National Park of American Samoa lets you sample some beautiful scenery while living like a local in a Samoan village setting.

Call it the journey of the frogs, or the salamander migration, but in the coming weeks River Road in Delaware Water Gap National Recreation Area will be closed overnight to allow for these amphibians to reach the other side of the road.

A lot of American naturalization ceremonies take place in courthouses, and a few take place in national parks. But this Friday is believed to be the first time such a ceremony ever took place inside a cave in Mammoth Cave National Park.