Olympic marathon champion Eliud Kipchoge will lead an attempt to run the first sub-two hour marathon tomorrow.
Three elite African athletes, Kipchoge, Lelisa Desisa and Zersenay Tadese, will run exactly 63 years after Roger Bannister became the first person to break the four-minute mile.
Three-time Boston Marathon winner Desisa, from Ethiopia, and Eritrean half-marathon world-record holder Tadese are aiming to become the first men with Kenya's Kipchoge to break two hours for 26.2 miles.
The Breaking2 project comes from sportswear giant Nike and takes place tomorrow morning at the Monza F1 track in Milan.
But it will not be an official world record attempt due to variables like pacers entering mid-race and drinks being given to runners via mopeds.
The three men, who have been training since last year for the attempt, will take 17-and-a-half trips around a 1.5-mile loop aiming to break a barrier no-one has ever done before.
The world record is held by Kenyan Dennis Kimetto, at 2:02:57, set at the 2014 Berlin Marathon.
It will start at 5:45am local time - 4:45am Irish time - with Nike live streaming the race, which is closed to the public, via their website and Breaking2 Facebook page while also providing updates on Twitter.
Nike have said the track surface has ideal temperature (54 degrees average), wind (2.6 miles per hour) and altitude (600 feet above sea level).