20 Free Adventures at National Parks
A short hike leads to a hot spring that bubbles up near the Rio Grande in Texas' Big Bend National Park. Early settlers thought the dissolved mineral salts in the water had healing powers. Visitors can test the theory by taking a soak in the 105-degree pool in the foundation of an old bathhouse.
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Stargazers flock to Grand Canyon National Park in Arizona every June for a weeklong star party with nightly slide shows, telescope viewing, and ranger-led constellation tours. No registration is required, and there are observation sites on the north and south rim of the canyon.
Visitors who want to explore Yellowstone's backcountry with an expert can participate in a guided five-hour Ranger Adventure Hike to such places as the Yellowstone River, Avalanche Peak, Garnet Hill, and Lone Star Geyser. Groups are limited to 15 or 20 hikers and reservations are required.
Shutterbugs can get a better feel for landscape photography during camera walks through Yosemite National Park in California. Led by staff photographers with the Ansel Adams Gallery, walks are offered four days a week, limited to 15 participants. Topics may include camera basics and Adams' famed work in the park.