A retired US soldier has chosen next Sunday’s Walled City Marathon to run his 500th marathon.

To mark the landmark achievement, the organisers have issued Dr Richard Holmes (pictured) with the number 500.

Since beginning Army Officer Candidate School in 1977, he has run over 88,000 miles (142,000 kilometres), more than three times the circumference of the earth.

These miles include:

:: At least one marathon in more than 60 different countries.

:: At least one full marathon on 42 different islands.

:: More than 60 marathons run entirely on islands.

:: More than 100 marathons and ultra-marathons, run off-road through forest, mountain, polar or desert trails.

:: In 2012 he won the 60-and-over category in both the Egyptian Marathon in Luxor and the Hogeye Marathon in Arkansas, and took third in his age group in the world's most northerly marathon in Spitsbergen on the Svalbard Achipelago north of Norway.

:: Also 2012, he won the overall Day 5 marathon of the Savage Seven, despite the field including fresh first day racers and it being his fifth consecutive day of running a marathon race.

:: On New Year’s Day in 2013, he won the overall Savage 7 race with the lowest cumulative time for seven consecutive daily marathons (averaging 4:46 a race), besting second place by almost six hours.

:: In 2013, he became the only person to have run a marathon in Antarctica wearing a head-to-foot penguin suit, and completed the "Run with the Horses" marathon in Wyoming wearing a horse!

:: In an eight day period in 2013, he completed a 100K race (62.1 miles), climbed Moun Kilimanjaro and then ran the Mount. Kilimanjaro marathon, being the oldest finisher in all three events.

:: In 2014, he completed the Polar Bear Challenge on the ice cap of Greenland wearing ice pitons, the oldest finisher in a half-marathon followed by a full marathon on consecutive days colder than 12 degrees F (-12 C).

:: Also last year, he became the first runner ever to complete 3 marathons in each of the 10 provinces and three territories of Canada.

:: In 2015, he was the oldest by 13 years to complete at least 95 miles in the Delirium 24 Hour Trail Race.

:: Also this year, he completed his fifth Antarctica marathon, becoming only the second runner to have run five marathons on all seven continents.

:: He was 12th of 29 finishers (counting only those who finished all five days) in running the "Dustbowl" series of five marathons in five states in five days, two days after he completed a marathon in a sixth state.

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