While most national park visitors no doubt focus on the landscape illuminated by the sun, going underground is an incredible experience. One of my favorite national park treks was at Mammoth Cave National Park in Kentucky, where I spent five or six hours crawling around on my belly during a "Wild Cave Tour." It was a memorable experience, one I won't soon forget.
    Another great park experience for spelunkers can be found at Carlsbad Caverns National Park in southeastern New Mexico. Though perhaps not as famous as Mammoth Cave, this complex contains more than 100 limestone caverns.
    But it's a park better known for trees than caves that is making news today. At Sequoia and Kings Canyon National Parks comes word that researchers have discovered a previously unknown cave, one with several rooms that are more than 50 feet across.
    Displayed in the cave are "soda straws" up to 6 feet in length, cave curtains and ribbons of multi-colored flowstone embedded with crystals. Named "Ursa Minor" after an ancient skeleton found in the cave and thought to have come from a bear, the cave also harbors a lake that could be as much as 100 feet across.
    The researchers, working for the Cave Research Foundation, also report several new species.
    It's long been known that Sequoia contains quite a few caves, and one of them, Crystal Cave, is open to public tours. No immediate word on whether this new cave, which will be closed to the public for the immediate future while research continues, is actually located in Sequoia or Kings Canyon, or both.