The Rimrocks don't seem secretive at first glance.
They appear too obvious, too solid, too here-and-now to harbor any frail mysteries.
Rising impressively over Billings, the palisades form the most prominent natural formation in the city. The Rims anchor the city's identity, giving it what many towns and cities don't have.
"We are so lucky to have two natural features — the Rims and an undeveloped river front," said Joyce Jensen, a local historian.
"The Rims are so awesome."
The Rims also hold many secrets.
The sandstone prow that divides the lower part of the city from the Heights has been explored by humans for centuries.
Many left their mark here — from ancient pictographs to contemporary love notes scratched into rock.
Here are a few of the secrets hidden in the Rims.
The Rimrocks provide many places to explore.
One is "Devil's Kitchen," a deep crack in the Rims above 11th Avenue North that leads to a cave.
When Gazette photographer Larry Mayer descended into the cave, he reported that it "smells like bats."
Devil's Kitchen has been popular with generations of Billings kids. When Jensen's father was a child in Billings during the 1920s, he visited the cave.
The Rimrocks may have been the location of the Immel-Jones Massacre during fur-trading days.
In May 1823, Robert Jones and Michael Immel were leading a group of 30 Missouri Fur Co. trappers through the Yellowstone Valley.
As they passed through a narrow passage, Blackfeet attacked them and killed seven trappers, including the two leaders, and wounded four others.
Although some have speculated that the site of the massacre was near present-day Park City, the late John Popovich of Billings thought that it happened near the Rims where Main Street meets Alkali Creek.
In an article in The Billings Gazette in 1992, Popovich said that the loss of nearly $15,000 worth of beaver furs during the attack was devastating for the Missouri Fur Co. and that the company disbanded the next year.
Blasting during construction of Sixth Avenue North in the early 1900s unearthed seven human skulls, perhaps the remains of the slain trappers.
The Heffner Stone Quarry at the Rims was the first big business in Billings after the railroad, Jensen said.
William Hefner's quarrying equipment may have come into Billings on one of the first trains.
After trains brought in supplies to Billings, Northern Pacific officials wanted something to ship out to increase the company's profits.
Heffner loaded up the empty cars with sandstone building blocks cut from the Rims.
Business really boomed after Heffner had a stretch of the Rims from Mountain View Boulevard to Virginia Lane federally certified as fireproof sandstone building materials.
At one time, 50 men were working at the quarry located against the Rims behind what is now Montana State University-Billings.
Heffner sandstone was used in local buildings and foundations, too.
The Western Heritage Center is the only sandstone building using Heffner stone that has not been facaded over left in town.
The quarry equipment was sold for scrap during World War II.
Blocks of sandstone from the old quarry form a traffic barricade at the first pull-off viewing area east of the airport on the south side of Airport Road.
At least five sets of stairs have been cut up the Rims on the Billings side of the Yellowstone River, Jensen said.
Most of the stairs have been eroded to the point of being unusable. Starting from the eastern end of the Rims, here's a look at those steps:
— Above North Seventh Street, a set of stairs go up a coulee near the Face-on-the-Rims pictograph.
— A set of stairs was carved into the cliffs by the Chamber of Commerce in 1910 as a way to get people to the top of the Rims to sightsee before North 27th Street was extended. The top of the stairs is just east of a dying cottonwood tree directly north of the Montana State University-Billings dorms. The bottom of the stairs is behind the MSU-Billings Physical Education Building.
These are the best set of stairs on the Rims, Jensen said, although the lower part has crumbled and it's hard to get up from the bottom.
— A set of stairs was cut into the Rims north of Macona Lane. Local residents at one time referred to these as the "Boy Scout steps."
— A set of stairs was cut by Rocky Mountain College students starting about Placer Drive behind the Rocky campus. They lead to a metal sculpture of a figure with outstretched arms.
— A set of stairs was cut into the Rims at Arvin Lane so the children of Charles O. Myers could come down to school. Metal posts still mark where steps were.
On the other side of the river, Jensen has heard that there may be two sets of steps on the Four Dances cliffs.
When Billings backed Helena for the location of the state capital, the city was promised the state prison.
A prison building, which may have started out as a private home, was constructed of sandstone northeast of what is now North Park at the top of North 16th Street near the Rims.
For reasons that are unclear, it never was used as a prison. It was bought by Austin North who developed it into a country club with places for horses, a lake with boats and a baseball field, Jensen said.
In 1933, it caught fire, and the inside was gutted. The sandstone blocks were hauled away and used in other buildings.
The Myers Trail was a private road that went from where Sky Ranch Drive is now down to County Club Circle, about the 2000 block of Rimrock Road.
It went to a private home built on the Rims by Charles O. Myers between 1913 and 1917.
The trail wasn't cut into the Rims as Zimmerman Trail was. Instead, local residents described it as a trestle supported by cables that hung out into thin air.
The Myers home later became a nightclub called the Skyline Club, then the Bella Vista Club and later back to the Skyline Club, which later burned.
Two tunnels cut through the Rims, Jensen said. One is a passage for the Billings Bench Water Association irrigation ditch. The other is at Echo Canyon, where the railroad tracks go through.
Carol Weller Timm was a junior in high school in 1974 when she and Margaret Kilbourne were senior Girl Scouts and in charge of a Junior Encampment for younger Scouts.
Some how the idea of a community-service project came up, and it was decided to plant iris, yucca and other native plants that didn't need a lot of moisture.
In the spring, the Scouts planted the flowers and other plants along the road up to the airport.
Dewey Hansen of Billings said that, in 1959 or 1960, after Airport Road had been widened, his Senior High Key Club planted yucca along the east side of the 27th Street North near Eastern Montana College, which is now MSU-Billings.
The dry environment on the Rims suits animals that don't necessarily need open water to survive, said Ray MulÃ©, regional wildlife program manager with the Montana Fish and Wildlife and Parks Department.
Rims-dwelling animals get moisture from plants or other animals that they eat and take advantage of rain water that temporarily pools in the rocks.
Animals living in the cliffs include yellowbelly marmots, cottontail rabbits and mule deer.
The Rims are a good place to see raptors or birds of prey because there are plenty of small animals to feed on and the cliffs provide thermals for raptors ride when looking for food.
Turkey vultures, prairie falcons, great-horned owls, cliff swallows, rock wrens and common night hawks all may frequent the cliffs, said Allison Puchniak, FWP native wildlife species biologist.
The Rims probably are home to western rattlesnakes, small sagebrush lizards, red-black and yellow-striped milk snakes.
At least four species of bats may hang in crevices and caves on the Rims: little brown myotises, pallid bats, western small-footed myotises and spotted bats.
Smaller critters are bushy-tailed wood rats, deer mice and least chipmunks.
For more on each animal go to FWP online field guide: fwp.mt.gov/fieldguide.
In spring, many species of wildflowers are blooming on the Rims, said Jennifer Lyman, professor of botany and environmental sciences at Rocky Mountain College.
This time of year, five species of sagebrush are blooming: big sage, fringed sage, sagewort, silver sage and green sagewort.
A type of aster, the purple liatris also blooms in the fall.
Ripening fruit includes the wax current that grows under pine trees. Aromatic skunk bush provides seeds for birds and animals.
The dominant species on the Rims, the Ponderosa pine, has been hit hard by drought. Some trees are dying because of a lack of enough moisture.
Grasses now in bloom are bluebunch wheat grass (the Montana state grass), prairie sand reed, blue grama grass, Indian rice grass and needle and thread grass.
Lyman encouraged visitors to the Rims to stay on established trails. There is a very fragile connection between plants and soil, particularly during a drought.
If the ground is disturbed, cheat grass and other weedy plants will move in and crowd out the native species.