What's behind faces of Mount Rushmore?

We were standing under the noses of the presidents, looking up.

A rubble pile sprawls under the iconic portraits. It was left when the mountain was blasted, drilled and carved away to create images of Washington, Jefferson, Roosevelt and Lincoln.

"There are 450,000 tons of rock on the talus slope," said ranger Brian McMahon. He told my tour group that if the presidents were carved to their full height, they would stand more than 400 feet tall.

From the boardwalk at the foot of the mountain, I could see the magnitude of Rushmore. A mountain had literally been remade in the image of men.

The pile of stone at our feet left the impression that the carving had just happened. In midday sun, the bright white granite of the presidents' faces contrasted with the ruddy, weathered stone around them, the way the flesh of a freshly cut apple stands out from the color of its skin.

In his 30-minute talk, McMahon spelled out the basic story of Rushmore, and something about the accomplishments of each president.

A fixture in ads, political campaigns and movies, Mount Rushmore is easy to dismiss as a cliche — the quintessential mid-America tourist stop. This year, I stopped to consider it again with fresh eyes and came away with a much different, more complex picture.

The self-styled "Shrine of Democracy" is mainstream America's civic holy mountain. A record 2.9 million visitors made a pilgrimage to it last year.

Rushmore is also a herculean engineering accomplishment. It's a fitting symbol of American ambition, and the sculptor knew it: "American art ought to be monumental, in keeping with American life," said Gutzon Borglum.

For all the superlatives, Rushmore's saga also has its troubling plot twists. The whole messy story of its making is also achingly American.

To start with, there's the fact that Rushmore honors four white guys by blasting apart a mountain in the middle of Indian country.

Then there's Borglum's ties to the Ku Klux Klan. He befriended Klan leaders and advocated their causes during the years he spent working on the Confederate memorial at Stone Mountain in Georgia.

Furthermore, not everyone is enamored of the gantlet of tourist traps and screaming billboards on all roads leading to Mount Rushmore — from Holy Terror Mini Golf to Bear Country, USA.