New Yorkers eat more hot dogs than people in any other city! On today's Please Explain, find out all about the history of hot dogs and how they're made. Also, actress Laura Dern talks about her latest role in "Recount" as former Florida Secretary of State Katherine Harris. A look at a new film about the real-life rescue of 60 orphaned Chinese children in the 1930s. States of the Union is all about South Dakota. Plus: author and screenwriter David Benioff.