The Obama Administration has been blocking access to national parks the world over (see Normandy), and nothing is sacred. In Shanksville, Pennsylvania, there is an open-air memorial to those killed in Flight 93 -- the plane that, on 9/11, was intended as a missile aimed at Washington, DC. The heroes on that flight prevented far greater loss of life by forcing the plane down into that field. The land around the memorial isn't even controlled by the National Park Service, but rather the state game and wildlife commission.
H/T: Patriot Post