Eliud Kipchoge has become the first marathon runner to break the two-hour barrier, recording a time of 1 hour 59 minutes 40 seconds in Vienna.
He had previously pushed the mark close in a similar attempt at the Monza Formula One racetrack near MIlan in 2017.
Kipchoge ran 2:00:25 on that occasion, but added extra pacemakers and allowed fans to line the streets for this attempt, as he made sporting history in Austria.
Who is Kipchoge?
Kipchoge is perhaps the best candidate in the world to attempt such a historic achievement in breaking the two-hour barrier for the marathon.
A four-time champion of the London marathon, having won the last two editions, as well as a two-time winner in Berlin and a solitary victory in Chicago to go with his Olympic gold medal.
What is the 1:59 challenge?
Ineos have sponsored the event, which will take place around the 4.3km stretch on the Prater Hauptallee in Vienna, Austria, with 4.4 laps required to complete the marathon distance.
Elevation will remain comfortably flat, though it will fluctuate between 1.8 and 4.0 metres. One request of Kipchoge since Nike Breaking2 was to involve fans, meaning the route will be lined by spectators in order to provide him with support.
Watch the above video as Eliud Kipchoge attempts to make history.
A reminder: The sport's governing body, the IAAF, will not recognise the run as an official record because it is not in open competition and it uses in and out pacemakers.
Kipchoge, 34, the reigning Olympic champion who set an official world record of 2:01.39 at the Berlin marathon in September last year, missed out by 26 seconds when he previously attempted to break the two-hour barrier in Monza in May 2017, a race run without spectators.
For those just joining us, Kipchoge is making very good progress.
He has hit the hour-mark with a healthy 11 seconds to spare.
The projected finish time is currently 1:59:48.
Kipchoge is on target in his bid to run an unofficial sub-two hour marathon as he completed the first half of his attempt at Vienna's Prater Park.
The 34-year-old marathon world record holder completed the first 21 kilometres in 59.35 minutes, 11 seconds under the two-hour pace.
However, there were a few spots of rain which had not been expected and which could hamper his attempt.
The last five kilometre splits have all been at precisely 2:50 each.
An incredible effort from Kipchoge and his team.
Eliud Kipchoge's wife, Grace, is watching very nervously: "I am nervous but also excited. I am happy for him. Kenyans are very excited for Eliud to do what no human has ever done - they're waiting!"
Here come the final pacemaker team...
Ten minutes remaining. And Kipchoge is six seconds clear!
Kipchoge's projected time currently stands at 1:59:50...
HE'S DONE IT!
Final time: 1:59:40.2.
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