WBEZ brings you fact-based news and information. Sign up for our newsletters to stay up to date on the stories that matter.You think the Chicago marathon is tough? How about New York, or Boston? Those runs are like trip on a merry-go-round compared to The Barkley Marathons. Based on a failed prison escape, the Barkley takes entrants over 100 miles of the roughest, most mountainous backwoods Tennessee terrain imaginable. 1000 have tried. Only 14 have finished. Filmmaker Annika Iltis talks about the race and the film ahead of two weekend screenings at the Gene Siskel Film Center.