A marathon race covers 42.195 kilometres, a distance standardised in the early twentieth century.

The longer version

The distance was not fixed until 1908, when a London course was extended so the finish passed in front of the royal box, and that extra stretch was later frozen into the rules. Earlier races at the revived games had been run over shorter courses of roughly 40 kilometres. The odd 195 metres at the end is the residue of a one-off layout.

Because the number is a historical artefact rather than a physiological threshold, it has no special meaning for performance. Race walking, road relays and split timing all had to adapt to a standard that came from architecture rather than sport science. Courses are now measured with a calibrated bicycle and include a small allowance so the route is never short.

Where this entry sits

Facts here look at the rules, equipment and odd histories behind familiar sports and games, from balls and rackets to cards, boards and playing fields. Expect small details about scoring quirks, stadium design and the long story of the Olympic Games. The full list sits on the Sports and Games page, where every entry is listed in order.