On the morning of October 12, Eliud Kipchoge, the best marathoner on earth, will set off from the Reichsbrücke Bridge in Vienna, Austria, with the goal of traversing 26.2 miles—42.195 kilometers—in less than two hours, almost half a minute faster than any person in history.
A little less than 120 minutes later, the world will know whether he succeeded.
The sub-two-hour marathon is the last great barrier in distance running. Elite athletes have been closing in on the milestone for more than a century, but only in the past few years have they started to come close. Kipchoge holds the official world record of 2:01:39, which he set at the Berlin Marathon in 2018.
But as the running world (and its sponsors) have grown obsessed with breaking the two-hour barrier, they’ve sought to engineer the perfect race to finally see if a human could do it. And in that ideal-marathon bubble, Kipchoge has gotten even closer than 2:01:39.
In 2017, the Kenyan attempted to break the two-hour barrier at Italy’s Formula One race track, in Monza. He came agonizingly close, completing the race in 2:00:25, too slow by an average of less than one second per mile. An exhibition event sponsored by Nike, conditions in Monza had been so carefully controlled that the race was ineligible for world record consideration. Still, Kipchoge had come closer than many thought possible. As he said after the race: “The world now is just 25 seconds away.”
On Saturday, at 8:15 am local time (2:15 am ET), Kipchoge will make his second attempt at a sub-two-hour marathon at another exhibition event, this one organized by global manufacturing company Ineos. And while no one can predict the future, it looks like he has a solid chance of pulling it off. Conditions Saturday morning in Vienna look to be even more favorable than in Monza. Assuming he runs a smart, injury-free race, the following four factors will dictate Kipchoge’s success—or his failure.