it sounds like the super bowl of ma masto chism.c's matt gutman checks it out for our series "into the wild." >> reporter: some go to brazil for the beaches, the famed cuisine, the exotic wildlife. we came for the pain. >> ow, ow, ow. >> ahh. >> oh, my god. >> feet up. >> reporter: specifically, the soul-destroying slog called "the jungle marathon." an ultramarathon. 149 torturous miles every seven days. once ape year, some of the world's most elite athletes pay thousands of dollars -- >> got my number. >> reporter: to suffer through mind-bending agony in this jungle paradise. >> come on, guys. >> reporter: shirley thompson runs the event. a veteran of multiple ultras herself, she's got the build of a hummingbird but the mentality of a drill sergeant. >> your penalty if you're late for the start -- wow wow, you look pretty. >> reporter: a perfect place for former beauty keeps. >> even color coordinated. >> reporter: we arrive on day one where we meet dr. julie goldstein, a former miss florida, and current veterinarian. running this