The White House's exterior walls are made of white painted Aquia Creek sandstone that was quarried by slaves. This is the same stone that was used to build the Capitol building.
James Hoban designed the White House after winning a competition that Thomas Jefferson, then Secretary of State, and President George Washington organized in 1792. Hoban was born in Ireland and trained as an architect there. Legend has it that Jefferson, himself an architect, entered the contest under a pseudonym and lost. The White House has been renovated several times since it was first built; however, the exterior walls are the same walls that were initially constructed.