Saturday morning, on a flat, straight, tree-lined avenue in the heart of Vienna, Eliud Kipchoge become the first person ever to break two hours in a marathon. He finished in 1:59:40, averaging 4:34 pace per mile.

The time trial, dubbed the 1:59 Challenge and sponsored by INEOS, a chemical company based in the U.K, was Kipchoge’s second attempt at breaking the two-hour barrier for 26.2 miles. During a similar Nike-backed experiment in 2017 at a racetrack in Monza, Italy, he came close, clocking 2:00:25.

Since then, the 34-year-old Kenyan set the world record of 2:01:39 at the 2018 Berlin Marathon. He’s also the 2016 Olympic champion and has eight World Marathon Majors titles between London, Berlin, and Chicago.

Eluid Kipchoge portrait
photo: INEOS 1:59 Challenge

In the days leading up to the event, Kipchoge compared the breakthrough to the moon landing. Over the years, he’s become an extreme fan favorite around the world, not just for his extraordinary athletic talent, but for his warm personality, infectious smile, and his Zen-like approach to his pursuits. Along the way, he tries to encourage fans of all ages to dream big.

“This race means a lot,” Kipchoge said. “I just have to make that click in people’s minds that no human is limited.”

“His running is a gift to all of us,” Shalane Flanagan said, on the INEOS 1:59 Challenge live broadcast.

Not everything went according to plan. Although the forecast called for lower humidity, it hovered at 90 percent and it was about 49 degrees Fahrenheit. It started raining around the halfway point.

Like the 2017 exhibition, his time won’t count as a world record, because organizers pulled out all the stops to make the historic result possible—some of those efforts make it ineligible, which have turned sport purists off to the experiment.

Kipchoge was given fuel bottles by supporters on bikes, his intake monitored by nutritionists to ensure he ingested just the right amount of carbs along the way. He was also aided by five teams of seven pacemakers, who swapped in and out nine times throughout the race against the clock.

Photo: Jon Super for The INEOS 1:59 Challenge

The carefully choreographed V-shaped formation of some of the world’s fastest track athletes followed a car the transmitted green laser lines on the ground to keep them on time. The 41 pacemakers included American athletes Matthew Centrowitz, Hillary Bor, Bernard Lagat, Lopez Lomong, Shadrack Kipchirchir, Stanley Kebenei, and Paul Chelimo. A number of Kipchoge’s countrymen and training partners kept Kipchoge company, and other notables such as 12:43 5,000m runner, Ethiopian Selemon Barega, and the three Ingebrigtsen brothers of Norway.

The major deviation from the first time Kipchoge went for the sub-two-hour mark was the course, which unlike the racetrack, was on public roads to allow for spectators to cheer him on. Kipchoge has said that he is motivated by the support of the crowds.

Apparently it worked. After his pacemaking duties, Matthew Centrowitz, the 2016 Olympic gold medalist in the 1500 meters, said during an interview on the broadcast that the spectators were close and loud, making it difficult for the pace teams to communicate with each other.

“It’s so exciting out there,” Centrowitz said. “The energy is through the roof.”

Photo: Jed Leicester for The INEOS 1:59 Challenge

Among those supporters were Kipchoge’s wife, Grace, and his three children. Remarkably, it was the first time his family has traveled to watch him perform.

The course was also specially designed to optimize Kipchoge’s chances. It was a 9.6K out-and-back on Hauptallee, with 90 percent of it run on a straightaway, and traffic roundabouts serving as the turning points on either end of the laps. The “Performance and Meteorology” teams advised on the best date and start time based on predictions for optimal weather—between 41 and 48 Fahrenheit, low humidity, and little wind.

And, Kipchoge also got by with a little help from his sponsor Nike. He wore a new version of the Vaporfly called the Next%, which keeps the 4%’s carbon fiber plate to increase efficiency and propel the runner forward, but adds more foam to the midsole.