File: First lady Michelle Obama (AP Photo/Pablo Martinez Monsivais)

Today, Washington Post columnist Petula Dvorak called for more people in the United States to acknowledge the enormous contributions that slaves made to this country’s history and its most famous monuments.

When I read Petula’s column, it reminded me of a story I wrote in February 2009, when first lady Michelle Obama invited about 180 students from D.C. schools to the East Room of the White House for a celebration of African American History Month. During that visit, Obama explained to the students that several milestones in black history had touched the White House.

“Did you know that African-American slaves helped to build this house?” Obama asked the students, in a poignant moment during the early days of President Obama’s administration.

Michelle Obama stood on a stage in the East Room. On either side of the stage were huge oil paintings. On one side was a painting of the first first lady, Martha Washington, and on the other, a painting of President George Washington.

Obama shared other moments in black history with the students. “Did you know that right upstairs in a bedroom called the Lincoln Bedroom, President Lincoln signed the Emancipation Proclamation that marked an important step forward in ending slavery? Did you know that happened right here?”

She told the students about Rutherford B. Hayes, who was president in 1878 when soprano Marie Seilka became “the first African-American artist to perform right here in the White House. That was in 1878. Did you know that? Because I didn’t know that.”

Obama explained the roles of Martin Luther King Jr. and other civil rights leaders who met in the White House with presidents Kennedy and Johnson to talk about ending segregation.

“Pretty cool, huh?” Mrs. Obama said.

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