If you're interested in 18th century warfare, and aren't tongue-tied by Spanish, the folks at the Castillo de San Marcos and Fort Matanzas national monuments are looking for you.

All trails at Whiskeytown National Recreation Area in California have reopened for the summer season—and just in time for the park's Waterfall Week. A number of trails in the park have been closed due to the risk of mudslides, after large wildfires in the park last summer.

Peregrine Falcons, once teetering on extinction, are regulars at Acadia National Park. Bald Eagles, also once feared to be ready to blink out, have rebounded incredibly and are highly visible in many national parks. During a week-long canoe trip in Yellowstone National Park last fall I was blown away by the birdlife. But how is the overall "state of birds" in America these days? Unfortunately, things aren't entirely as they appear.

Park officials have confirmed that a recent rockfall at Yosemite National Park was in fact the largest such documented event in the park more in than two decades. Part of a popular trail buried by the debris from the event remains closed.