The First Battle of Bull Run (First Manassas) was fought near Manassas, Virginia, on July 21, 1861. The Second Battle of Bull Run (Second Manassas) was fought in the same area August 28-30, 1862. Now officials at Manassas National Battlefield Park are fighting to restore the battlefield’s historic sightlines and protect them from encroaching development.

Fierce winter storms and shifting shoals gave birth to the "Graveyard of the Atlantic," where thousands of ships have foundered since record-keeping began in the 16th century. Beginning late in the 18th century, rescuers began patrolling the East Coast in search of such wrecks.

Zion National Park has become a magnet for canyoneering enthusiasts. With more than four dozen remote and technical slot canyons feeding into Zion Canyon, the park is just about as good as it gets for practitioners of this rapidly growing extreme sport.

High ozone levels have prompted Great Smoky Mountains National Park officials to issue an air pollution advisory for today and Saturday. So if you're visiting the park, you might want to ease back on your physical activity, especially if you already have respiratory problems.