To celebrate July 4, the New York Public Library displayed its rare copy of the Declaration of Independence, featuring Thomas Jefferson's condemnation of the slave trade. But that passage was dropped in the final version of the document to appease southern delegates. Bestselling author of "Don't Know Much About History" and historian Kenneth C. Davis joins "CBS This Morning" to dispel some commonly-held myths from U.S. history and shed light on some of its most famous names.