Pheidippides did it once and became a legend. Brian Mills did it over 800 times...but you might be forgiven for not knowing who he is. He is a runner and 'it' is the marathon - all 26 miles and 385 yards of it - and for some people, once is not enough.
Brian Mills is rumoured to have a butterfly tattoo for each of his 800 plus efforts. And Brian is not the only one who has notched up three digits of gruelling athletic endeavour.
The 100 Marathon Club, also known as the Hell's Angels of Running and Running Sluts (running one race whilst thinking of another) is growing in number every year.
This is a club with no prejudices and only one prerequisite for membership - the completion of 100 marathons.
It is full of colourful, contrasting characters with idiosyncratic personalities and diverse lifestyles.
They make up a gargantuan melting pot of humanity linked by one common desire - to run...and run ...and run. But who would want to run 100 marathons or more? And why? How do they find the time, the money, the energy? Are they crazy? Find out by reading their stories. Some will make you laugh, others will make you cry, some may even inspire you to run a marathon. Believe it or not, these are ordinary, everyday people like you.
Although when you have finished laughing and crying, you may still not be sure whether they are crazy or passionate.
But you - as they do when they run - will have a lot of fun along the way.