|Ineos 1:59 Challenge with Eliud Kipchoge|
|Date: Saturday 12 October Time: 07:15 BST|
|Coverage: Watch live on the BBC Sport website and on the Red Button|
Eliud Kipchoge says he hopes to show there are "no limits" by becoming the first person to break the two-hour marathon barrier on Saturday.
The Kenyan, 34, is attempting the feat for the second time in the Ineos 1:59 Challenge in Vienna, having missed out by 26 seconds in Monza in 2017.
He is the current world record holder, though this attempt will again not count as an official record as he will be assisted by rotating pacemakers.
"I'm running to make history," he said.
"I'm running to show that there are no limits, no human is limited."
Olympic champion Kipchoge, who won the London Marathon for the fourth time earlier this year, clocked two hours, 25 seconds in a similar attempt as part of Nike's Breaking 2 project at the Monza grand prix circuit in Italy.
This time he will run the 26.2 miles over 4.4 laps of a 5.97-mile course in Prater park in the Austrian capital, with the route consisting of two 2.67-mile stretches and two small loops at each end.
The location was selected because of the favourable climate, excellent air quality and almost completely flat terrain, with only 2.4 metres of incline over the entire route.
The attempt is being funded by petrochemicals company Ineos - owned by Britain's richest man Sir Jim Ratcliffe - which also sponsors the cycling team of the same name.
The Ineos team assessed the weather conditions before selecting Saturday as the attempt date, with Kipchoge also hoping the course will be lined with spectators, unlike his previous attempt.
"The course is extremely good - I feel more prepared and I am confident," said Kipchoge.
"It's not about thinking, 'Am I going to do it?' - I have tried it the first time and the second time, I will do it."
Kipchoge will be assisted by 41 pacemakers, who will be helped to maintain a constant speed by a leading pace car that will beam lasers onto the road.
The pacemakers will rotate twice each lap and Kipchoge will be handed his drinks and energy gels from a bike every 3.1 miles, instead of picking them up from a table as in normal marathons.
These aids are not allowed under IAAF rules, which is why athletics' world governing body, the IAAF, did not recognise his first attempt as the official marathon world record and will not sanction this one either.
Kipchoge broke the official record by running 2:01:39 in the 2018 Berlin Marathon, while Ethiopia's Kenenisa Bekele fell two seconds short of that mark in this year's race.
"That run in Berlin and this run in Vienna are two different things," said Kipchoge.
"Berlin was running and breaking a world record - Vienna is running and making history, like the first man to go to the moon.
"I am trying to stay as calm as possible."
Kipchoge was asked if breaking the two-hour barrier would be a boost for athletics' image after recent controversies.
Leading coach Alberto Salazar has been banned from the sport for four years after being found guilty of doping violations and there were sparsely populated stands for much of the recent World Championships in Doha.
In response, Kipchoge said: "I will give you an example: In a garden there is flowers and there are weeds.
"In Vienna, we are talking of the flowers. Let us concentrate on the flowers which can prosper and make everybody in this world be happy."