This October marks 75 years since the completion of iconic American sculpture known as Mount Rushmore featuring the massive heads of four US presidents – George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln - fixing their gaze towards the horizon from their eyrie in the Black Hills of South Dakota.

But why was the 18 metre high sculpture, known to some as the Shrine of Democracy, constructed in the first place? It was South Dakota’s state historian, Doane Robinson, now known as the “father of Mt Rushmore”, who first had the idea for a sculpture as a way of drawing tourists from across the country to his state. His initial idea was for granite pillars known as the Needles to be sculpted into heroes Western heroes such as explorers Lewis and Clark, the Sioux chief Red Cloud and Buffalo Bill Cody.

Mount Rushmore

PICTURE: Russell Weller/

In 1924, he contacted Danish-American sculptor Gutzon Borglum, who was then already working on a giant carving - a memorial to confederate leaders on Stone Mountain in Georgia (it wasn’t eventually completed until 1972) – and invited him to visit South Dakota to talk about the possibility of creating a new giant carving there. Borglum did so and it was he who suggested the possibility of carving the heads of US presidents – initially just Washington and Lincoln - in place of Robinson's original proposal with the premise being the significant impact each of the presidents had upon shaping the nation.

It was while on a second trip in August, 1925, that Borglum came across Mount Rushmore – which, oddly, was named for a New York City lawyer - and decided upon it as the location for the sculpture.

Funding was clearly a critical issue and raising it was a task Robinson apparently took on enthusiastically, aided by the likes of John Boland, mayor of nearby Rapid City and US Senator Peter Norbeck. Despite opposition from local Native Americans and environmentalists, US President Calvin Coolidge - who enjoyed holidaying in the area - formally dedicated the work on 10th August, 1927.

The carving began in October the same year and in 1929, during his last days as president, Coolidge signed legislation setting aside $US250,000 for the project and created a commission to oversee its completion with Boland as its president (Robinson, to his disappointment, was excluded but continued his support of the project nonetheless).

It was a monumental task with some 400 workers - each apparently climbing 700 steps every day just to clock in - removing more than 400,000 tonnes of rock from the rockface (it now lies heaped at its base) during the 14 years of the monument's construction, using what were then new methods involving dynamite and jackhammers. Remarkably, no lives were lost during what was clearly a dangerous job.

Washington’s was the first head to be dedicated - on Independence Day, 1930 – and Jefferson’s, which had been relocated from the right of Washington’s to the left due to weakness in the stone, was second – August, 1936, followed by Lincoln’s – September, 1937 – and Roosevelt – July, 1939.

The original concept had been to sculpt the presidents from the waist up but a lack of sufficient funding to cover such a task meant that, in the end, the sculpture depicted only their heads. As it was, the project cost just under $US1 million.

The monument as a whole was dedicated in 31st October, 1941 - 75 years ago, but Borglum didn't live to see it – he died in March that year leaving his son Lincoln with the task of finishing the monument.

The Mount Rushmore National Memorial now receives almost three million visitors a year. While pop culture references to the monument are many, perhaps the most well-known came in Alfred Hitchcock’s film, North by Northwest (although all the filming took place in a studio and not at the site itself apparently after permission to film there was refused).