The Decatur House

S First Lady Michelle Obama (C) is surr...US First Lady Michelle Obama (C) is surrounded by 6th graders from Fairfax, Viginia's Willow Springs Elementary School during a surprise visit to the Decatur House in Washington, DC, May 22, 2013. The Decatur House is a National Trust for Historic Preservation Site which received a $ 1 million grant from American Express to preserve the Slave Quarters structure and fund educational programming.     AFP PHOTO/JIM  WATSONJIM WATSON/AFP/Getty Images

Jim Watson/AFP

Michelle Obama, the US first lady, meets sixth graders from Willow Springs elementary school in Fairfax, Virginia, during a surprise visit to Decatur House, a historic building in Washington, on Wednesday. Decatur House is a National Trust for Historic Preservation site, which received a $1m grant from American Express to preserve its slave quarters and fund educational programming