August marks 80 years since the United States dropped two atomic bombs on the Japanese cities Hiroshima and Nagasaki, killing an estimated 210,000 people. Setsuko Thurlow, who survived that day, shares her experience and her message for us all amid today's nuclear tensions. Then, Megan Williams speaks with historian and journalist Garrett Graff and national security analyst Joe Cirincione about how this event paved the path to our current nuclear world, and where things may go next.