The Secret Underneath the Lincoln Memorial: A Hidden Foundation Opens to the Public After a Century

To call Washington a swamp is a metaphor, but it's also literal fact. When planners began work on the Lincoln Memorial in the early 1910s, they faced a real sinking problem. Their solution — a massive concrete foundation hidden from view — became one of the capital's best-kept secrets for more than a century.

That secret is the Undercroft, a term usually reserved for the vaulted basement of a medieval castle or cathedral. Here, 120 concrete pillars plunge 50 feet into the ground, reaching bedrock to support the massive marble structure above. The space spans 50,000 square feet, nearly twice the size of the memorial itself, according to Interior Secretary Doug Burgum, who recently gave reporters a rare tour.

“They're still dripping,” Burgum said, pointing to stalactites formed by rainwater seeping through cracks in the granite. “As the rainwater comes through, it picks up calcium.”

Starting this June, visitors will finally be able to see the Undercroft for themselves. A new museum, suspended directly beneath the memorial, will open its doors — thanks in large part to philanthropist David Rubenstein, who donated a quarter of the $69 million needed for the transformation. “I thought it would be a good idea to give the Lincoln Memorial more of an educational role,” Rubenstein said. “You can't really be a great country if you don't honor and understand your history.”

Rubenstein hopes the museum will deepen visitors' understanding of Abraham Lincoln — a figure whose life was far less grand than the marble above suggests. “He had a very complicated life,” Rubenstein said. “A lot of tragedy. A lot of his children died young. A complicated marriage. But in the end, he rose to the occasion and became, I think, our greatest president.”

Some exhibits will also tell the story of the memorial itself. Howard University historian Edna Greene Medford sees the monument as a stage for America's shifting 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, performed her concert on the steps of the Lincoln Memorial — delivering the opening notes to a decades-long struggle for civil rights. In 1963, Martin Luther King Jr. stood at those same steps and declared, “Now is the time to rise from the dark and desolate valley of segregation to the sunlit path of racial justice.”

“The memorial becomes not just a symbol of freedom for Black people, but for various groups,” Medford said. “They feel this is their memorial, and they interpret freedom in their own way.”

The museum touches on this history, but it opens at a time when some national park sites are removing signs and reviewing exhibits related to slavery and racism. The administration calls it “restoring truth and sanity to American history.” But with slavery and racism so fundamental to the story of the Lincoln Memorial and its new museum, the question becomes: Who gets to determine that truth?

Secretary Burgum acknowledged the tension. “There's a place to have current cultural debates,” he said. “And then there's a place to just tell and celebrate our history. We're not a nation without flaws, but we're a nation based on continuous improvement. We may have over-rotated toward a point of massive self-criticism because it was politically expedient. It's important, when 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 Edna Greene Medford

Story produced by Dustin Stephens. Editor: George Pozderec.