A team of 100 Royal Air Force personnel has smashed the world record time for a 100x10,000 metre relay.
It was a mammoth task from the 100 RAF men and women, who each ran 10km, one after the other in a relay format, for 64 hours, 36 minutes and 22 seconds.
They averaged around 39 minutes per 10,000m to beat the record, covering a total distance of 1,000,000m.
The effort beat the previous record, of 69 hours, 6 minutes and 52 seconds, which had stood since 2015, with four and a half hours to spare at RAF Cosford.
For three and a half days a succession of forces runners kept the baton moving across the Cosford track, with many having travelled hundreds of miles to take part in the record attempt.
The mettle of the runners was seriously tested during the darker hours, while cameras were dotted about the track, with meticulous record-keeping vital to supply the evidence to Guinness to ratify the effort.
Senior Aircraftman Michael Kallenberg, one of the Air Force's top long-distance runners, organised the endurance running record attempt as part of its centenary celebrations.
Having coordinated the attempt from start to finish, it was fitting that he was the man to cross the line. He told Forces Network:
"It was amazing... Having a great crowd down here, it was nice to come home to that really.
"It's the end of hours, days of hard work from 100 hard-working athletes."
One of the other organisers, Flight Lieutenant Ben Lyman, said:
"We didn't believe in our wildest dreams that we'd get this far... We thought we'd be a lot, lot closer [to the record than bettering it by over four hours]."
The attempt was kicked off on Monday by the chairman of the RAF Athletics Association, Group Captain John Lawlor, who ran the first leg.
Group Captain Lawlor had suggested to SAC Kallenberg and other top RAF runner Ben Livesey that the Air Force try to break a record in its centenary year.
The fastest time was set by Sam Mitchell, who clocked 31 minutes, 54 seconds, with Livesey 20 seconds short of that effort.
The RAF last entered the athletics record books in 1984, when Steve Jones broke the marathon world record, before his time was surpassed the following year.
Celebrations surrounding the new record are now well underway, however, although it will take several months to be given the official thumbs-up by Guinness.