It's Memorial Day, a day that Americans often conflate with Veterans Day, but in fact, it has its own unique history.   Just to clarify: Memorial Day, once known as Decoration Day, was founded just after the Civil War; Veterans Day, once known as Armistice Day, was founded after World War I. Veterans Day is in November. And Memorial Day, of course, is the last Monday in May. To give us a more comprehensive history of the origins and evolution of Memorial Day, Kenneth C. Davis joins. Davis is the author "Don't Know Much About History" and the forthcoming "Don't Know Much About the American Presidents."