Spartathlon in Athens/Sparta
A 246-kilometer ultramarathon from Athens to Sparta held every September since 1983, born from a 1982 test by Royal Air Force officers of whether the ancient messenger Pheidippides could plausibly have covered the distance in a day and a half, with a 36-hour cutoff and a finish ritual at the statue of King Leonidas.
In 1982, five Royal Air Force officers led by John Foden set out to test a specific historical question: whether Herodotus's account of the Athenian messenger Pheidippides running from Athens to Sparta in a day and a half to seek military help before the Battle of Marathon was physically plausible.