Do you know that  a marathon is a long-distance running race with an official distance of 42.195 kilometres
I knew it in miles but not KM.  I'm not much of a runner, 5K is about my limit.  What about you?
Been running all my life. The first run was an event done  in commemoration of the fabled run of the Greek soldier Pheidippides, a messenger from the Battle of Marathon to Athens, who reported the victory.