Ken Burns documents the worst human-made ecological disaster in American history, when a frenzied wheat boom on the southern Plains, followed by a decade-long drought during the 1930s, nearly swept away the breadbasket of the nation. Vivid interviews, dramatic photographs, and seldom-seen movie footage bring to life incredible stories of human suffering and perseverance. Includes bonus features

From the age of dinosaurs to ancient Egypt, from early cave drawings to continued mass sightings in the United States, each episode gives historic depth to the questions, speculations, provocative controversies, firsthand accounts, and grounded theories surrounding an age-old debate: Did intelligent life forms from outer space visit Earth thousands of years ago? Do they visit us now?