"The Heart of Lincoln" is one of 7,000 silent films listed by the Library of Congress as being lost forever. Now, the 1915 movie about Abraham Lincoln and Civil War life, has been found. NBC explains how film student Dan Martin found the 16-millimeter film while going through boxes during his summer internship at Lauro's Historic Films Archive in Greenport, New York. The film has now been cleaned and digitized so it will be preserved forever.