CODY, Wyo. — If you're planning a vacation in Yellowstone, consider side trips to a trio of unusual destinations in Wyoming on your way to and from the park: Devils Tower, Cody and Thermopolis.

Devils Tower: This natural stone formation is a national monument, managed by the National Park Service. It's located in northeast Wyoming, not far from the South Dakota border, about 80 miles from the Black Hills town of Deadwood. It's an awesome sight, rising 867 feet from its base or 1,267 feet above the Belle Fourche River, "upthrust against the gray sky as if in the birth of time the core of the earth had broken through its crust," as Native American writer N. Scott Momaday put it.

The tower's top appears flat from a distance, but the National Park Service describes it as being slightly domed, about the size of a football field. But Devils Tower's most distinctive features are what appear to be long vertical stripes covering the sides. These are actually parallel columns of rock that fractured as the molten magma that formed the tower cooled eons ago.

More than 20 tribes consider the tower a sacred site, and many Native American stories describe the lines in the rock as claw marks from a bear. It's not unusual to see bundles of colored cloth or other religious offerings in the park around the tower.

A relatively easy trail, about 1.3 miles, circles the tower. Some 5,000 climbers a year scale the tower; climbers must register with the park service beforehand. Details at www.nps.gov/deto.

Cody: This town was founded by Bill Cody, also known as Buffalo Bill, in 1896. Yellowstone's east entrance is just 52 miles away, but it's worth spending a day or so here, rather than just using the town as a jumping-off point for the park.

The Buffalo Bill Historical Center — www.bbhc.org/home — tells the story of the famous Pony Express rider, military scout, buffalo hunter and showman, whose Wild West Show — which starred Annie Oakley and Lakota Chief Sitting Bull among others — toured for three decades. Visiting the center is a great way to learn about the history of the West, with lively displays that even kids who hate museums will find captivating, including fascinating photos and artifacts. The museum is open daily March through November (Thursday to Sunday, December through February). Tickets are $15 ($10 for ages 6-17).

In 1902, Buffalo Bill opened the Irma Hotel — www.irmahotel.com — in town, named for his daughter. The hotel, decorated in period decor, is still there, with rooms running about $150 a night. Its restaurant serves up some of the best food in town, with a hearty, reasonably priced menu of ham, beef, chicken and pasta among other options. The lunch buffet is $9.50 (Sundays $13) and a prime rib buffet supper is $23.

Cody also calls itself the "rodeo capital of the world." The Cody Nite Rodeo is held June through the end of August; if you've never seen a cowboy ride a bucking bronco, it's a must. Details at www.codystampederodeo.com.

Thermopolis: On a rocky hill overlooking this quiet town of 3,000 is a hand-painted sign: "World's largest hot springs," with an arrow.

These springs gush millions of gallons of mineral water a day at a constant temperature of 135 degrees. Cooled to a more comfortable temperature, the water can be enjoyed by visitors in several different venues around town.

The landmarked Plaza Hotel, located within Hot Springs State Park, has a spa fed by the springs. The hotel, founded in 1918, is on the National Register of Historic Places. Renovated in 1999, it's operated by Best Western and is a comfortable place to spend the night. (Rates range from about $130-$160, depending on room size and date.)

You can also walk to a small, scenic natural pool in the park or sample the waters in a public bath house on park grounds. Kids will enjoy the slides at two funky water parks — Hellie's TePee Pools — www.tepeepools.com/ — or Star Plunge — www.starplunge.com.

Another local curiosity is a large thumb-like structure called the Tepee Fountain. The formation dates to 1903, when a pipe was installed to vent the hot springs. A tepee-shaped block was later placed around the pipe, and as the water cascaded over it, layers of mineral deposits formed vertical columns. As the water cooled, different types of algae bloomed, adding color to the formation.

For more information about Thermopolis, visit www.thermopolis.com.