Many large cities around the world have a yearly marathon event. Today it’s Copenhagen (and possibly other cities too).
The marathon distance today is 42,195 kilometers (if I use comma as decimal point) which resembles 26 miles and 385 yards or 26.22 miles (if I use a dot as decimal point).
So even if we today agree about the distance we might represent that distance in various ways. The distance has however varied during history as seen in the table with the length of the Olympic marathons.
Well, if the Greek runner called Pheidippides (sometimes spelled Phidippides or Philippides) took the long but flat Southern route from Marathon to Athens it would have been around 42 kilometers. If he took the shorter but steeper Northern route it would only have been around 35 kilometers.
What about me? Oh, I’ll go for 42,195 kilometers – on the bike.