When Indian running coach Samir Singh set himself the goal to run 10,000 kilometres in 100 days you'd be forgiven for thinking he was in a little over his head.
Not only would this challenge see him run 100 kilometres each day for 100 days, but it would also require a wealth of mental, emotional and physical strength as well as a multitude of self-belief. He would especially need the emotional strength and self-belief when he came just 36 kilometres from reaching his goal on the final day of his run.
Maybe that's why he was dubbed 'The Faith Runner'.
On Sunday, overcome by the pain of blisters, mental and physical exhaustion and illness, he was forced to stop the run early. After falling ill with gastrointestinal infections and fevers, Singh had to run 150 kilometres on the final day of the run to make up for the time he had taken off with illness.
He was only able to run 114 kilometres of the final 150, meaning he managed to get in 9,964 kilometres in 100 days.
To put that into perspective, Singh's run is more than double the distance between the east and west coastlines of Australia (4,030 kilometres each way) and is equal to the distance between the eastern and western borders of Russia (almost 10,000 kilometres). The run also totals the equivalent of a quarter of the Earth's circumference (40,075 kilometres).
But why would someone do this?
The power of the human spirit, that's why.
Each day, Singh started in the early hours of the morning, running from the slums in Mumbai's north to the business district in the south. He lived off just six dollars a day.
He told the AFP that he has been unemployed for nine months and has relied on people's donations of shoes, clothing and equipment to get him by.
"My journey of running 100 kilometres per day is very challenging but I wanted to show the endurance limit of human spirit," he told AFP before his final run.
By the end of the run, Singh weighed just 40 kilograms, having lost 16 during the course of his self-set challenge.
Now it's time for Singh to rest before he takes on his next challenge, which will see him run over 40,000 kilometres. That run will be equal to the Earth's circumference.