Eliud Kipchoge ran a marathon in 1:59:40, so why is it not the world record?

Because it was staged for him, not run as an open race. On 12 October 2019 in Vienna, Eliud Kipchoge ran 42.195 km in 1:59:40.2, but World Athletics could not ratify it. Forty-one pacemakers, rotating in and out in groups of seven, ran with him. Hydration was handed over by a coordinator on a bicycle. There was no open competition. For these reasons it was not eligible to be ratified as a marathon world record.

The setup was designed to cut losses. Pacing lasers kept the group at an exact speed. A V-shaped formation shielded Kipchoge from the wind. The course, a flat park avenue, rises only 2.4 metres in total. The event was created specifically for him, and also to market a Nike shoe.

It came after a near miss. In 2017 at Monza, Kipchoge ran 2:00:25, 25 seconds short, on a day warmer than the ideal temperature.

Before all this, Haile Gebrselassie thought two hours might fall in 20 to 25 years. Kipchoge said afterwards he wanted to show that no human is limited. Guinness World Records recognised the run, but under its own titles, not as an official world record.