This image released by the National Park Service shows Steve Lorenzetti, Deputy Superintendent of Planning, left, and Robert A. Vogel, Superintendent of the National Mall and Memorial Parks conferring with civil engineer Ned Wallace, right, inside the Washington Monument Wednesday, Aug. 24, 2011, amid debris that fell to the floor after a 5.8 magnitude struck the Washington area on Aug. 23. (AP Photo/National Park Service)
David Campbell, with the National Park Service, shovels snow off the steps of the Lincoln Memorial on the National Mall in Washington on Thursday, Jan. 27, 2011, after a large snow storm swept through the area the previous evening. (AP Photo/Jacquelyn Martin)
Vice President Joseph R. Biden Jr. speaks with National Park Service Director Jon Jarvis (left), and Grand Canyon National Park Superintendent Steve Martin (in hat) at the Grand Canyon in Arizona. Mr. Biden's daughter, Ashley, also was on hand. (Associated Press)