It's the endurance event that embraces weekend joggers and the best runners in the world.
This Sunday thousands of people will take part in one of the most demanding physical challenges - the London Marathon.
As part of the build-up, Special Report has been following two amateur runners as they prepare to tackle the 26.2 mile course. Read their stories here.
But first we checked in with three-time London Marathon winner Paula Radcliffe, who explained why the race is so special.
"I grew up as a child watching it and it was all about that Sunday morning in April watching everybody from the charity runners and the elite runners," said Radcliffe. "I've got early memories of seeing Ingrid Kristiansen setting a world record in 1985.
"It's just about the way the whole city coms alive with it - the vibrancy of it, the colour of it; you run past all of the London icons. It's really hard to put into words what it's like - as I say to people, the best way to find out is to take part."
Over 800,000 runners have finished the London Marathon since it was first held in 1981 and as Hugh Brasher, the joint-race Director explained, the event has become a huge fundraising occasion.
"One of the original goals was to show that humanity could come together to celebrate effectively life and it really is a day on which London comes together," explained Brasher.
"You have at least half-a-million people out watching the event and supporting it at different stages; it's just stunning to be part of it. It is an elite race - you are 'competing' against some of the best runners in the world but actually it is a street race for London.
"Last year the marathon raised £51.8m - that's the runners themselves - and that's a Guinness World Record and in its time so far, the marathon has raised over half-a-billion pounds for charity. People see it as a challenge, which it is - running 26.2 miles is not easy."
Yet Special Report's Marathon bloggers Anna Edwards and John Hibbs have both accepted the challenge.
Mum-of-three Edwards, who has just turned 40, is running in aid of the Friends of West Hatch RSPCA. She believes that ordinary people can do the extraordinary.
"I think everybody can come up with a reason not to do something because it's just human nature but if it's something that you want to do and you organise yourself you can find the time to do it," Edwards explained.
Meanwhile John Hibbs is going in search of his third London Marathon medal after his sister, Viki, was diagnosed with lupus at the age of just 25.
"A lot of it is about my sister - getting to that finishing line and seeing her," said Hibbs, who suffers from arthritis in his knees.
"She is the motivation that gets me through the pain I suffer; but I know my sister is in pain every day from the condition she suffers with so it's worth it."
So ahead of the day, who better to offer a few tips and words of advice than Radcliffe herself?
"On race day itself don't change anything: run in the same shoes you've practiced in, the same kit that you've worn before, practice the race breakfast - that kind of thing - and just pace yourself. Don't go off too hard because that's really easy to do because the atmosphere will lift you and push you on; so try and rein that in a little bit until halfway and then let it go."
Radcliffe, now 38, is not only a legend of the London Marathon but has won two New York Marathons and a Chicago Marathon. Plus, she also holds the women's record of 2:15:25 hours.
So how does she prepare?
"I generally have an ice bath the night before, followed by a warm shower, so I'm not going to be freezing, and a massage and then I get up about four hours before, have something to eat which might be some porridge with some, honey, banana or hot chocolate; I'll have an energy drink and then get down to the start," she told Special Report.
"My warm-up routine is usually pretty much the same - a 10-15 minute jog, half-an-hour of stretches and strides.
"Waiting for the gun to go is the most nervous time for me; once the gun goes and I start, I'm just glad to get going and glad to get into my running and enjoy it."
Don't worry if you missed 'Special Report - The Marathon' because it will be available on Anytime from Wednesday.