If you’re hoping to squeeze in an inexpensive getaway before September, try putting one of the country’s 58 national parks on your list. Every park has great scenery and knowledgeable rangers, but you’ll find that some parks have unique or unusual attributes as well.
In one park, for example, afternoon tea with popovers is a long-held tradition. Another celebrates a nightly ritual involving hungry bats.
Curious about what else makes some of our national parks a bit different? This would be a great weekend to find out. The National Park Service is waiving entry fees for the 100-plus parks, landmarks and historic sites on August 14 and 15.
First and oldest
In 1872, Yellowstone National Park became this country’s first official national park. In addition to the Old Faithful geyser (which you can watch from home), the park offers activities ranging from hiking and fishing to wagon rides and llama packing. You can even bring along your own horse.
Hot Springs National Park didn’t officially become a national park until 1921. But because it was established by Congress as the Hot Springs Reservation back in 1832, this park with hiking trails, an historic bathhouse district and hot springs earns the title of the oldest unit in the national park system.
Go there: Admission to Yellowstone National Park is $20 per car (good for seven days). There is no admission fee for Hot Springs National Park.
Smallest and largest
At 5,550 acres, Hot Springs is the country’s smallest national park. That means that during a visit you should have time to hike some of the park’s 26 miles of trails and explore downtown, with a stop at the Bathhouse Row. You might even squeeze in a soak in a traditional Hot Springs bath.
At more than 13 million acres, Alaska's Wrangell-St. Elias National Park & Preserve is the country’s largest. The park is open year-round, but the best time to drive, hike, camp, raft or hunt is during the summer and before the Alaska winter sets in — usually sometime in mid-September.
Go there: While there are no entry fees, entry gates or even any official park service campgrounds at Wrangell–St. Elias, some commercial services are available. But plan ahead — this is not the place to be left out in the cold.
Filling a hole, or caldera, left by the collapse of a volcano, southern Oregon’s Crater Lake is six miles long and 1,943 feet deep. Surrounded by lava cliffs that can reach 2,000 feet, it’s the deepest and, because the water is so pure, possibly the bluest lake in the United States and among the top 10 deepest lakes in the world. The lake rarely freezes, but Crater Lake National Park does get about 45 feet of snow each year.
Go there: Even with all that snow, Crater Lake National Park is open year round. The best time to visit is during the summer, when boat and trolley tours are offered and when it’s possible to walk, bike and drive around the lake. There’s $10 fee per car (good for seven days).
Longest and deepest cave
At 367 miles long and close to 400 feet deep, the spectacular and, at times, somewhat spooky Mammoth Cave in Mammoth Cave National Park is the longest mapped cave system in the world. The cavernous underground chambers and labyrinths are home to 130 animal species (including 12 tiny, eyeless, unpigmented cave-dwelling creatures) and have been a tourist attraction since 1816.
With 83 separate caves, New Mexico’s Carlsbad Cavern in Carlsbad Caverns National Park also seems mammoth. But at 1,597 feet, one of the cavern’s more than 110 limestone caves is considered the country’s deepest. In addition to fantastic and unusual rock formations, Carlsbad Cavern is also home to more than 17 species of bats, including as many as 1 million Mexican free-tailed bats.
Go there: Mammoth Cave National Park in Mammoth Cave, Ky., has 14 miles of cave trails, 31 miles of river and 85 miles of hiking trails. There’s no fee to enter the park, but fees are charged for Mammoth Cave tours, which can last from 30 minutes to more than six hours. Carlsbad Caverns National Park charges an entrance fee for self-guided tours of the 8.2-acre Big Room area of the cave (adults, $6; children 15 and under, free; tickets are good for three days). Guided tours, including some to areas not accessible on the self-guided tour, are also available for a small fee. There is no fee to hike in the park, to attend Bat Flight Programs or to watch hundreds of thousands of bats fly out of the cavern at dusk each night.
See you later, alligator ... after awhile, crocodile
With more than 1.5 million acres, Everglades National Park is the largest subtropical wilderness in the U.S. The park is home to frogs and toads, more than 360 species of birds, close to 300 types of fish, and more than 40 different mammals, including the Florida panther, Everglades mink, weasels, fox, bear and bats. Plenty of reptiles live here too, including turtles and tortoises, lizards, and 50 different kinds of snakes, including Burmese pythons. (Scared yet?) The Everglades is also the only place where you’ll find both the American alligator and the American crocodile.
Go there: There is a fee of $10 per car (good for seven days) to enter the park. In addition to fishing, boating, canoeing and hiking, visitors can walk along boardwalk trails or take a ranger-guided tour on a boat or a tram.
Set on 800 square miles on the forested border of Tennessee and North Carolina, Great Smoky Mountains National Park draws up to 10 million visitors a year. What’s the attraction? It’s easily accessible (about a four-hour drive from Atlanta or Nashville) and offers everything from auto touring on scenic roads to wildlife viewing, fishing, hiking and horseback riding. The park is also home to an exceptional collection of almost 80 preserved and restored historic houses, barns, schools and other buildings.
Go there: The park does not charge a fee for entry. The National Park Service even offers a downloadable set of Smokies Trip Planner guides to make sure you find your way around.
Largest living thing
It’s hard to get your mind, let alone a tape measure, around things that are as tall as 26-story buildings and as wide as city streets. But experts have declared several Giant Sequoia trees in the Sequoia National Park to be giants among the giants. According to the National Park Service, when last measured, the General Sherman Tree was the largest Giant Sequoia at 274.9 feet tall and 102.6 feet around. Several of the tree’s neighbors are record-setters as well.
Go there: A seven-day vehicle pass to Sequoia and Kings Canyon National Parks in California is $20. You can learn about giant trees in the Giant Forest Museum and then visit the General Sherman Tree and four other record-setting Giant Sequoias in the Giant Forest.
Hottest and driest
Have a glass of water handy? With an average of less than 2 inches of rain a year (and in some years no recorded rainfall at all), Death Valley National Park is the hottest and driest spot in North America. At 282 feet below sea level, the park’s Badwater Basin is also the continent’s lowest place. Sound like fun? It can be, but unless you’re the hearty 4X4-on-backcountry-roads sort, stick to short hikes and air-conditioned drives that take you to places like Natural Bridge, the Harmony Borax Works (home of those infamous Twenty Mule Teams) and Scotty’s Castle, a mansion built with the proceeds from an imaginary mine.
Go there: Visitor centers at Death Valley National Park are open year round, but the best time to stop by is sometime between October and April, when the air cools down. Whenever you go, be sure to visit Scotty’s Castle, a working museum with living history tours of the mansion, the grounds and the underground tunnel.
Hawai'i Volcanoes National Park includes petroglyphs, 150 miles of hiking trails, and the chance the see the daily, fiery output of Kilauea, the world’s most active volcano. Erupting steadily since January 1983, the volcano has been producing up to 650,000 cubic yards of lava a day. That’s enough lava, says the Hawaii Convention and Visitors Bureau “to resurface a 20-mile long, two-lane road daily.”
Go there: Hawai'i Volcanoes National Park, on the Big Island, is open 24 hours a day. The park charges a $10-per-vehicle entry fee. Kilauea’s actions and output change daily, so ask the rangers at the Kilauea Visitor Center for the safest and most up-to-date tips on where to go to see the volcano’s ash plumes and lava flows.
On a recent visit to Maine’s Acadia National Park, President Obama and his family did what plenty of other tourists do — they rode bikes, admired the scenery and took a ride up the 1,532-foot Cadillac Mountain, the tallest mountain along the North Atlantic seaboard. No word, though, if they stopped at the park’s Jordon Pond House Restaurant to partake of a century-old park tradition: afternoon tea served out on the lawn, with a plate of fresh popovers and strawberry jam.
Go there: Acadia is on Maine’s Mount Desert Island. An entrance fee of $20 per vehicle (good for seven days) is collected from May 1 to October. The cost drops to $10 per car after October. A long list of free and low-cost ranger-led programs are listed in park’s newspaper (the Beaver Log) and online.
Harriet Baskas is a frequent contributor to msnbc.com, authors the and is a columnist for USATODAY.com. You can follow her on .