Each of the 26 miles of the London Marathon will be a tough challenge for all its 40,000 runners today.
But for one mum, each mile she completes will be made even harder because it marks each of the 26 weeks her daughter was ill for before she died of cancer.
Emma Furneaux is taking on the 26.2 mile race in memory of Elisha who was just 17 years old when she passed away from a rare condition known as undifferentiated soft tissue sarcoma.
“Elisha was ill for 26 weeks from diagnosis to her death,” said the mum-of-three from Gwynedd in Wales to the BBC.
“So I will be running a mile for every week she was ill and a little bit extra for good measure.
“I know it’s going to be hard physically but I’m excited.”
Elisha, who died in October 2016, was working as an apprentice at a nursery when she first started suffering from back pain.
She was given painkillers by a doctor and sent for an x-ray – but before the results came back, the tumour had spread to her spine.
When the diagnosis was finally made, the cancer had spread to her lungs, kidney and pelvis.
On the Just Giving page ‘Run4Elisha’, Emma wrote: “During the two years since Elisha’s death I have really struggled to find motivation to do anything.
“Then, whilst watching the London Marathon last year I decided to enter!”
She continued: “Although I started out as a complete non-runner, I have trained several times a week for many months and am feeling more and more confident that I can run a marathon! “
Emma has so far raised more than £5,000 for CLIC Sargent, the UK’s leading cancer charity for children, young people and their families.
But signs can include a soft, painless lump that “can’t easily be moved around and gets bigger over time”.
It may also cause tummy pain, a persistent feeling of fullness and constipation, coughing and breathlessness.