More than 38,000 runners, fundraisers and elite racers have lined up to take part in this year's London Marathon - making it the biggest in the event's history.
World record holder Paula Radcliffe, 41, completed her final competitive marathon, saying the "magic of the London Marathon" helped her through.
Paula Radcliffe has tweeted her thanks to the crowd who supported her during her last London Marathon.
She added that her memories "will last a lifetime and beyond".
A runner who took part in the London Marathon completed 21 miles before realising the "slight pain" he felt was actually a broken hip.
The London Marathon brings together thousands of people raising money for charity - not to mention some rather unusual costumes.
Nearly 38,000 runners will hope to complete Sunday's London Marathon making it the biggest event in its 35-year history.