Arlington Cemetery was the property where Robert E. Lee's home stood. People started leaving the corpses of soldiers that died in the Civil War (both sides) in his front yard and eventually they had to be buried. It just became a graveyard.
Also the construction of the Washington Monument was halted for years because of the war. All effort and materials went to the war effort and that's why the stones appear to be different colors.
Also the construction of the Washington Monument was halted for years because of the war. All effort and materials went to the war effort and that's why the stones appear to be different colors.