On Saturday morning in Italy, three Nike runners will attempt the impossible. The athletes—Eliud Kipchoge, Lelisa Desisa, and Zersenay Tadese—will compete in Breaking2, Nike's ambitious effort to log the first sub two-hour marathon time. This historic event will be streamed in its entirety above.

Participating athletes will wear the Nike VaporFly Elite sneaker, a concept car style that uses the brand's new ZoomX foam in the sole. This foam is paired with a carbon fiber plate, a piece of technology that's been the cause of some controversy in the lead-up to this race. These shoes are customized to the specific requests of the individual athletes, and will not be available at retail in the future. That being said, Nike has a takedown line in the works based around the same technology that's launching in June.

Completing a marathon in under two hours has long been an unachievable feat—the current world-record on an eligible course is Dennis Kimetto's 2:02:57 from the 2014 Berlin Marathon. While Nike's Breaking2 attempt won't be eligible for a world-record as the program's approach to pacing and fueling don't meet IAAF requirements, the company has said that it is more about pushing the limits of the human body than adhering to specific requirements around races. More background on Nike's efforts around Breaking2 is available here.