To call Washington a "swamp" is a metaphor, but also the literal truth. So, when planning began for the Lincoln Memorial in the early 1910s, builders faced a real sinking problem. Their solution led to one of Washington's best-kept secrets, hidden for over a century … until now.

Underneath the Lincoln Memorial is what's known as the memorial's Undercroft (a term usually reserved for the vaulted basement of a medieval castle or cathedral). Here, 120 massive concrete pillars sink 50 feet into the ground, down to the bedrock, to support the weight of the marble above.

The entire space, 50,000 square feet (almost twice the size of the memorial above), has never been seen by the public before, said Secretary of the Interior Doug Burgum. He also pointed out the stalactites: "They're still dripping. And of course, as the rainwater comes through cracks in the granite, it seeps down here, picks up calcium," he said.

Visitors will be able to see it for themselves starting this June, in a new museum hanging directly beneath the memorial. "I thought it would be a good idea just to have more of an educational role for the Lincoln Memorial," said philanthropist David Rubenstein, who helped bring the Undercroft out of the shadows, donating a quarter of the $69 million needed for its transformation.

"You can't really be a great country if you don't really honor your history and understand your history," Rubenstein said.

He hopes it expands our understanding of Abraham Lincoln, whose own life wasn't as grand as the marble above suggests. "He had a very complicated life," Rubenstein said. "He had a lot of tragedy in his life. A lot of his children died before they were very old. [He] had a very complicated marriage as well. But in the end, he rose up to the occasion and became, I think, our greatest president."

Some of the exhibits will also be about the memorial itself. Howard University historian Edna Greene Medford sees the memorial as a stage for America's changing ideas of freedom. "I think it's still about freedom, hope, and today it's about inclusion," she said.

In 1939, contralto Marian Anderson, barred by Whites-only policies at the city's indoor venues, moved her concert performance here, delivering the opening notes to a decades-long battle for civil rights where the memorial often took center stage.

As Martin Luther King Jr said on the steps of the Lincoln Memorial in 1963, "Now is the time to rise from the dark and desolate valley of segregation to the sunlit path of racial justice. Now is the time."

Medford said, "The memorial becomes not just a symbol for freedom for Black people, but it becomes a symbol of freedom for various groups. They feel that this is their memorial. And they are interpreting freedom in their own way."

The museum touches on this history, but it is opening at a moment when other national park sites are removing signs and reviewing exhibitions related to slavery and racism. The administration calls it "restoring truth and sanity to American history."

But with slavery and racism such a fundamental part of the story of the Lincoln Memorial and the new museum, who gets to determine the truth? According to Secretary Burgum, "There's a place to have current cultural debates. And then, there's a place to just tell and celebrate our history. We're not a nation without flaws, but we are a nation that was based on continuous improvement. And we may have 'over-rotated' towards a point of some kind of massive self-criticism, 'cause maybe it was expedient, politically, in the short term. It's important, when we're using federal dollars, that we tell the story that celebrates this country."

The Undercroft invites visitors to see the Lincoln Memorial in its entirety – not just the ideal in marble above, but the work, the weight, and the imperfections underneath. A fitting view perhaps, for Lincoln, and for a country still gathering at his feet. 

    
For more info:

• Lincoln Memorial Undercroft tour info (National Park Service)
• Lincoln Memorial (National Park Service)
• Philanthropist David Rubenstein
• Secretary of the Interior Doug Burgum
• Howard University professor emerita Greene Medford

    
Story produced by Dustin Stephens. Editor: George Pozderec.

See also:

• Abraham Lincoln and the preservation of democracy ("Sunday Morning")
• Abraham Lincoln's coat, and its hidden, bloody stories ("Sunday Morning")
• Time will tell: Historians on judging presidential leadership ("Sunday Morning")
• Almanac: Abraham Lincoln's beard ("Sunday Morning")
• Lincoln's funeral train is reborn ("Sunday Morning")
• Lincoln assassination: The other murder attempt ("Sunday Morning")