When title to all the lands, structures, and other property within the military battlefield area and other areas of Civil War interest at and in the vicinity of Kennesaw Mountain in the State of Georgia, as shall be designated by the Secretary of the Interior, in the exercise of his discretion, as necessary or desirable for national battlefield park purposes, shall have been vested in the United States, such areas shall be, and they are, established, dedicated, and set apart as a public park for the benefit and inspiration of the people and shall be known as the "Kennesaw Mountain National Battlefield Park."