More than 250,000 people entered their name into the London Marathon 2017 ballot.
Some will be running to beat their best time, some dressed as animals, cartoon characters and even London buses, and some just hoping to cross the finish line still standing.
But practically everyone whose name was pulled out of the ballot this year will have one thing in common. They are running to raise money for a charity or organisation that means something to them.
From dealing with mental health problems, living with life-changing medical conditions or overcoming traumatic circumstances - we tspoke to those running in Hertfordshire who will be "Running for a Reason" on Sunday, 23 April.
Robert Hiscocks (above) will run the marathon after hearing about the millions of people that the poverty charity Turn2us supports each year, and has raised more than £1,500 so far.
Robert, who works as an information technology project manager, decided to run as he is very concerned that so many people in the UK are often forced to choose between heating their homes and eating food, or who live in homes without cookers or curtains because they are unable to afford them.
Danny Byrne (above) will be running the London Marathon for head injuries charity Headway in memory of his mother.
Tricia Pilkington died last September after she suffered a serious head injury following a fall at her home. She was just 61.
Danny, 38, who lives in Watford, has been trying to get a place in the London Marathon for years.
He said: “I used to run quite a bit when I was younger but then I had a series of injuries when I was at university and had a metal pin put in one leg.
“I do bits and pieces to try to keep fit and healthy but running the marathon is certainly going to be a challenge.
“I have set a nominal target of £1,000; if I can do something that will help someone else then it is worth doing. Even if they have to drag me round I will complete the course.”
Lee Paterson-Bryant (above), 38, will become the first person to run the London Marathon on behalf of Watford Football Club’s Community Sports and Education Trust.
Watford runner Gary Venn will pull on his running shoes this month to tackle the London Marathon in aid of Alzheimer’s Research UK.
Gary, who works at the Wickes Support Centre in Watford, will be joined by colleagues Sam Wood and John Adams (pictured above) for the 26.2-mile race on Sunday.
The group will be spurred on by thoughts of friends and family members who have been affected by dementia.
The runners have pledged to raise £10,000 for Wickes’ charity partner, with the help of three other colleagues who are entering a Tough Mudder half marathon.
Paul Sycamore (above) will be running his 15th London Marathon on Sunday to raise money for a cancer charity.
When he first started raising money for the Roy Castle Lung Cancer Foundation a few years ago in memory of his wife’s aunt Chrissie, and then her mum Margaret, it was the least he could do to try and help others in their fight against lung cancer and lung cancer-related diseases.
Little did he know that one day he would be running the marathon in memory of his dad who passed away in October following a lung cancer-related illness.
Every £1 raised and every step of the 26 miles will be dedicated to Paul’s dad, Margaret, Chrissie and the many others who have suffered from this terrible illness.
Paul is attempting to raise £2,500 and has so far raised £1,390.
A woman with Asperger’s is running the marathon on behalf of the National Autistic Society.
Marianne Phillips (above) was told at primary school that she would never amount to anything.
However through great determination she obtained very good GCSEs and A levels and went on to Birmingham University. She now has a good job as an auditor in a well-known bank.
However she has not found life easy and has had to work far harder than most other people and develop coping mechanisms to get around her disability.
Taking part in the event for the National Autistic Society is a huge personal goal of Marianne’s.
In total, 1,000 people applied to run on behalf of the National Autistic Society but only 17 were accepted.
Marianne hopes her example will encourage others to be ambitious, and raise awareness about Asperger’s Syndrome and autism in general.
Alison Kelly Keegan (above) is the first ever marathon for Watford and Three Rivers Home Start support local families in their time of need. She has raised £1,500 so far with more to come in sponsorship.
Kellie Toombs (above), 23, is running for the RNIB for partially sighted and blind people, as she is partially sighted too.
Kayleigh Constable (above), 24, from Borehamwood, running for charity Age UK.
Sam Watts (above), 35, running the London Marathon this year on behalf of Pancreatic Cancer UK.
A Bushey man is hoping to raise more than £2,000 for a national blood cancer charity by taking part in the London Marathon.
Drew Somerston (above) will be taking on the famous 26.2 mile course in aid of Leukaemia CARE, a charity which offers support to patients, carers and health care professionals.
The 25-year-old trainee accountant has a personal connection to Leukaemia CARE as his father has Chronic Myeloid Leukaemia.
Luke said: “I was 12 when he was diagnosed and now I know more about Leukaemia CARE, I know I would have benefitted from the support services that the charity offers.
“Fortunately, my father is now in remission but I have a much better understanding of the disease. Now is my opportunity to help people can the best support they can.”
- Good luck to all those running on Sunday. We would love to hear from you if you are taking part. Email email@example.com to be included