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Kentucky

Hike through Mammoth Cave and learn the natural forces forming this National Park from ancient shallow seas to perpetual erosion
Texas

Camp along the Rio Grande and take an overland adventure through Big Bend National Park in southwest Texas on River
Texas

Boondock in Big Bend National Park's backcountry of southwest Texas along River Road near Mariscal Mine at the Fresno Campsite.
Texas

Call it quicksilver, cinnabar, or mercury. Texas's Big Bend National Park once produced a quarter of this malleable metal for