National Geographic’s Breaking2 documentary, that features Berlin Marathon hopeful Eliud Kipchoge on his quest to break the 2-hour marathon barrier, has been released.

The audacious Breaking2 attempt in Monza, Italy, saw 32-year-old Kenyan Kipchoge, miss the 1:59:59 mark, but he did post the amazing time of 2:00:25, unofficially the fastest time in history.

The documentary takes you on the fascinating journey with Olympic gold medalist Eliud Kipchoge, Lelisa Desisa, a two-time Boston Marathon winner and the half-marathon record holder Zersenay Tadese in their attempt to do the unthinkable.

On Sunday (September 24) Kipchoge aims to become a two time Berlin Marathon champion and possibly clock an official world record when he faces off against Ethiopia’s Kenenisa Bekele and Kenyan Wilson Kipsang. All three marathon greats have announced their intentions to break Dennis Kimetto, 2:02.57 record, set three years ago on the same German capital course.

Back to the Breaking2 Documentary, while critics dismissed the project by Nike as nothing more than a PR stunt, the effort by the men and the work that went on behind the scenes was real. You can watch the journey below and see the effort it took Kipchoge to shave more than two minutes off his previous best.