June 19th is called "Juneteenth", referring to the holiday when slaves in Texas, the western-most part of the u.s. in 1865, learned from arriving troops that they were free. It was a huge day of celebration and even a state holiday in Texas. Kenneth C. Davis speaks to Pat Farnack about Juneteenth and "In the Shadow of Liberty", his book about how five of our first seven Presidents were slave owners.