Runners from across the world will descend on the capital on Sunday to compete in the London Marathon.
For some, it is a battle of wills in the form of a bucket list tick. Something to prove to yourself that you can be tested.
Others will be running for charities and raising a few quid for those who need it.
Those taking part will be hoping for the perfect conditions.
A light drizzle might just mean an extra spring in your step, whereas glaring sunlight could have you reaching for the water bottles a little earlier than planned.
Something in between might just be ideal.
The course will be lined up and down by spectators in the form of family and friends, curious locals or even athletics enthusiasts - so here's hoping it's fair weather!
London Marathon weather forecast
The mass participation race, after the professional runners set off, will begin around 9:30am on the Sunday 3 October.
The elite wheelchair race begins at 8:50am, followed by the elite women at 9:00am and the elite men also at 9:30am.
Currently, the Met Office is a largely sunny morning and afternoon, with a less than 5% chance of rain between 9am and 2pm.
Things could get a little damp at 3pm when there is a 30% chance of rain, however this should clear up again by 4pm.
Wind speeds should remain relatively low throughout the day, reaching their peak at 34mph at 3pm.
As ever, this could be subject to change.
This is the UK, after all. So don't count out the chance of a downpour. Spectators will be minded to bring a raincoat just in case.
How can I watch the London Marathon?
Coverage will start on BBC Two at 8am and move over to BBC One at 10am, where it will stay until 2:30pm.
From here, the BBC iPlayer and Red Button will have you covered.
Highlights will be shown on BBC Two at 6pm.
If you want to watch then you can pick your favourite spot along the route, which has remained largely unchanged since the first race in 1981.
The course begins near Blackheath in Greenwich and turns west towards central London.
At mile 12, where runners will near the halfway point at The Shard and Tower Bridge, the course turns east again to Canary Wharf at mile 18.
It is then a quick dash back to the centre of London, this time on the north bank of the Thames, where participants will streak or stagger past the London Eye, Big Ben and the Houses of Parliament, before ending up on the famous red finishing straight of The Mall outside Buckingham Palace.
You can see a preview of the route here.
