A man known as 'World Guy' is pushing a globe across the United States to raise money for the American Diabetes Association.
Erik Bendl's travels began after his mother Greta, 54, died of complications from diabetes in 1987.
The loss haunted Mr Bendl, who was then working as a carpenter, and he wanted to do something to show that his mother's death was not in vain.
The answer lay in his garage: a giant globe given to him by a friend in 1988.
In the late 1990s, he did a 160-mile walk around Kentucky to promote the charity, and then in 2007 he became more ambitious and walked 430 miles from Louisville to Pittsburgh.
During the walks he talks to everyone about diabetes - about his mother, about how important it is to exercise and how diabetes can be controlled. He donates any money he receives to diabetes awareness groups, such as the ADA and the Diabetes Exercise and Sports Association.
So far, the 48-year-old has walked more than 2,200 miles in 23 states with the globe, travelling as far east as Acadia National Park in Maine and as far west as Pike's Peak in Colorado. He has hit New York City and Washington DC.
He is now on his fifth long walk, from Fort Lauderdale, Florida, to Savannah, Georgia, walking 10 miles each day.
"They don't ask me if I'm crazy - they tell me I'm crazy," Mr Bendl joked.