October 9, 2001

Canada, Mexico, and the United States were settled by people of roughly the same background, at about the same time. Yet the three countries developed different cultures. Anthony DePalma, international business correspondent for "The New York Times", talks about the history of the American continent, and how these three nations relate today. He explains why the United States is the dominant force of the North American continent, and how European nations are equal powers. His book is "Here: A Biography of the New American Continent".

Land plants probably originated much earlier than previously thought. Blair Hedges, molecular evolutionist, talks about his research, which estimates that land plants are 700 million years old. He tells us how the evolution of land plants has affected other animals and organisms. Hedges is from Penn State University.

Todd talks with journalist Tim Ecott about diving, and the world beneath the seas. Ecott talks about the history of diving and exploring underwater, and how diving has become a recreational pastime. His book is "Neutral Buoyancy: Adventures in a Liquid World".