A man from Cornwall who has stopped running marathons because they were too short is preparing to run 3,100 miles across the United States.
Bob will run the equivalent of two full marathons every day
Teacher Bob Brown, 35, from Stoke Climsland, is the only UK athlete taking part in Run Across America 2004.
The race starts in California on 12 June and is due to end in New York about 70 days later.
He is aiming to raise money for the charity Country Holidays for Inner City Kids (Chicks) from his trek.
The US challenge means he will almost run the equivalent of two full marathons every day for 70 consecutive days.
He will be competing alongside some of the world's top endurance runners in temperatures sometimes in excess of 38C (100F).
He has already travelled the world to take part in extreme races.
Three years ago he completed a challenge of greater distance, the 3,250-mile Trans-Australia
Footrace, running from the west to the east coast.
He is currently en route to Australia to acclimatise for the US event.
Bob, a primary school teacher born in Bushey, Hertfordshire, and a former Shaftesbury Harrier, ran his first marathon in 1989 but found that too short.
The same year he entered his first ultra race, running 80 miles.
In 1995, running as a complete unknown, Bob finished second in the World Triple Ironman Championships in France, which consisted of a 7.2-mile swim, 336-mile cycle and 78-mile run.
He has also competed in the world's longest and toughest triathlon - the World Deca-Ironman Championships in Monterrey, Mexico. Competitors had to swim 24 miles, cycle 1,120 miles and run 262 miles.
Of his latest run he said: "When I heard about the run across the United States I knew I had to do it."
"We're starting from Huntingdon Beach, just south of LA, going to Las Vegas, up through the Rockies to 10,000 feet, down to Denver, through the Great Plains, Indianapolis, and then finishing in New York."
Bob is raising money for his sponsor's selected charity, Chicks, which provides activity holidays for deprived and disadvantaged children.
People will be able to chart his progress on a website created by Bob and his pupils at Stoke Climsland school.