We've been catching up with marathon man Simon Kindleysides ahead of Sunday's big challenge.
Simon, from Blofield in Norfolk, is hoping to become the fastest person - and the first man - to complete the London Marathon in a futuristic exoskeleton suit. He expects it to take him around 35 hours over two days.
He's needed a wheelchair since a brain tumour five years ago. But now the father of three is back on his feet and hoping to raise thousands for the Brain Tumour Charity
Becky Jago caught up with him...
Simon Kindleysides, from Blofield in Norfolk, completed the London Marathon on Monday night after walking the race in an exoskeleton suit.
Chris Wright is running the marathon in memory of his daughter Demi who died from cancer aged just 22.
A Norfolk teacher will be donning her trainers and running the London Marathon to raise money for the hospital which saved her son.