The world record for male marathon runners is 2 hours, 2 minutes and 57 seconds. Elite runners are getting close to a time that almost seemed unthinkable a few years ago: running a marathon in two hours.
The chase continues this fall with major marathons in Berlin this Sunday and later Chicago and New York.
Here & Now's Meghna Chakrabarti revists a conversation with author Ed Caesar, whose book on a two-hour marathon comes out in paperback next month.
Ed Caesar, author of "Two Hours: The Quest to Run the Impossible Marathon." He tweets @edcaesar.
This segment aired on September 21, 2016.