A record-breaking 40,382 runners, including competitors from China, took part in the 37th annual London Marathon on Sunday - 1,242 more than 2016. This year, around 202 runners from the Chinese mainland signed up to take part, along with 144 from Hong Kong and 26 from Taiwan.

General view of runners at Westminster during the marathon.  [Photo/Agencies]

Competitors were given a royal send-off from Prince William, Duchess of Cambridge Kate Middleton and Prince Harry.

The event started in Greenwich, in southeast London, with runners making their way to Westminster, passing iconic London sites such as Tower Bridge and Big Ben before heading down the final stretch on The Mall.

The Royal trio was joined in supporting the runners by around 800,000 spectators who lined the capital's streets to cheer on the professionals, charity runners, and amateur competitors along the 42.2-kilometer course.

Some fun-runners chose to dress up as superheroes, animals, and cartoon characters while British celebrities and politicians also took part.

This year's official charity was the Heads Together campaign, which aims to break down the stigma around mental illness.

Many of the runners took part in the marathon to raise money for a charity or organization that means something to them but they were also given Heads Together headbands to wear in support of the "mental health marathon".

Last year, the event raised around 60 million pounds ($76 million) for charity.

Marathon organizers also wanted to highlight the many reasons why people took part in the run and asked participants to use the hashtag#reasontorun on social media.

Around 50 runners attempted world records during the marathon, including fastest marathon dressed as an emoji, fastest in a sleeping bag, and fastest in Wellington boots.

A gingerbread man, Minnie Mouse, and horse-drawn carriage carrying a queen could also be seen making their way from Blackheath to The Mall.

The oldest competitor was 83-year-old Kenneth Jones, who has taken part in every London Marathon since it started in 1981. The oldest woman was 81-year-old Eleanor Draper.

And the race was also about sportsmanship, with one runner attracting a lot of interest online after helping a fellow competitor over the line who was struggling with exhaustion.

They were both cheered home by Princes William and Harry and the Duchess of Cambridge, who had traveled to the finish line to witness the end of the race they had started.