WASHINGTON -- Michelle Obama says stories of toil and sweat by slaves once housed at a historic home within sight of the White House are an important part of U.S. history that must be preserved for future generations.

The first lady commented Wednesday as the owners of Decatur House announced a $1 million gift from American Express to preserve the nearly 200-year-old structure and pay for educational programs for students.

Officials say most of the money will be spent to preserve the building's former slave quarters.

It's one of the few remaining examples of slave quarters in an urban setting, and the only surviving proof that slaves were held near the White House.

Mrs. Obama said the stories of those slaves are as vital to the country's "national memory" as any other.