Mount Rushmore, which has more than two million visitors each year, turns 100 this year. Matthew Davis talks with CBS News’ Major Garrett on “The Takeout” about his new book, “A Biography of Mountain,” which dives into the monument’s sculpture, history and meaning. “People assume that the federal government was behind it from the very beginning, when really, my favorite part of the story is that the idea for Mount Rushmore was created by a state historian named Doane Robinson, who in the 1920s,