There's no denying the spectacle that is Mount Rushmore - the massive visages of four influential US presidents, peering out of the Black Hills from which they were carved.
Created by Danish-American sculptor Gutzon Borglum and more than 400 workers between 1927 and 1939, the 18-metre-high monument to democracy has been called "the world's greatest mountain carving" and is today South Dakota's premier tourist attraction, visited by nearly three million people each year.
But just 27 kilometres away, an even larger face has emerged from a craggy cliff, dwarfing Borglum's creation in every aspect.
Chin to scalp, it stands nine storeys high; in fact, all four Mount Rushmore heads could fit in its skull. Tourists gather under the cave-like nose, staring up into flared nostrils; most are unaware they are standing on the foundations of an outstretched arm, as wide as a highway with a tunnel-sized armpit.
This is the Crazy Horse Memorial - the world's largest outdoor sculpture-in-development. And as huge as the austere, proud face of the legendary Native American war chief Crazy Horse is, this is just the beginning - beneath his hand, pointing to the lands of his Lakota tribespeople, is the sketched outline of a horse's head, which, when completed, will be 22 storeys high.
From the chest of the horse to the flying locks of the Lakota medicine man, the total size of the finished sculpture-in-the-round will be 195 metres long by 171 metres high. That's bigger than the Great Pyramid of Giza.
More than 70 years in the making, this is a project with no deadline - there are still countless years to go before completion, and progress is painstakingly slow.
Unlike Mount Rushmore, the Crazy Horse Memorial is a non-profit undertaking, accepting no government funding; future work is reliant on ticket sales, gift shop sales and donations.
But that's the way the memorial's creator, Polish immigrant Korczak Ziolkowski, wanted it. To accept money from the government would negate the monument's underlying message: that the Native Americans, too, have great leaders.
"I want to right a little of the wrong that they did to these people," Ziolkowski said.
"If it's supposed to be done, the American people will make it happen."
It was back in 1929 when Ziolkowski, a New England-based sculptor who had earned his mountain-carving stripes on nearby Mount Rushmore, was approached by Chief Standing Bear to create a response to the presidential monument on behalf of the Native American people.
Working from a scale model, the first blast on private property in the Black Hills took place on June 3, 1948. Back then, the project was a one-man band. Ziolkowski lived like a pioneer, refusing to accept a wage, sleeping in a tent with no running water or electricity. Each day he would haul his digging equipment and explosives up hand-hewn steps, no mean feat for a man over 40.
"Every man has a mountain," he once famously said. "I'm carving mine."
In 1950, Ziolkowski married his geology intern, Ruth, who bore him 10 children - five boys, five girls - all of whom helped on the project. "It's definitely been a family project," Ruth, 88, tells me at the monument.
"Each of the youngsters had a talent or niche they could contribute." Ruth was also instrumental in setting up the visitor complex and the on-site Indian Museum of North America, an extraordinary collection of art and artefacts designed to complement the story being told in stone on the mountain.
Ziolkowski died in 1982, aged 74, and is buried in a mausoleum on the property.
His parting words to his wife were: "You must work on the mountain - but go slowly so you do it right."
And so it was to be. Ruth, seven of their children and several grandchildren today continue Ziolkowski's legacy, faithful to his vision every step of the way.
Ruth is still the driving force behind the project and her current goal is to finish the horse's head.
Although it is still far from finished, the Crazy Horse Memorial has become the "fifth head"; tourists visit it in tandem with Mount Rushmore.
From humble beginnings, it is now a much-beloved South Dakotan symbol, attracting more than a million visitors a year.
The writer travelled as a guest of Rocky Mountain International and South Dakota Tourism.
GETTING THERE Fly to Los Angeles (14hrs), then to Denver (2hr 17min) and then to Rapid City (1hr 18min).
The Crazy Horse Memorial is 27 kilometres south-west of Mount Rushmore National Memorial on Highway 16.
STAYING THERE Hotel accommodation is available in Hill City (14 kilometres north) or in State Game Lodge in Custer State Park, rooms from US$115 (NZ$137) a night.
- Sydney Morning Herald