Marathon running is considered one of Korea's national sports. For most of the year, there are at least two or three marathons held each weekend around the country. The large races, like the Seoul International in March and Chuncheon in October, draw upwards of 25000 runners.
Ultramarathons are a much cozier affair. The Incheon Ultramarathon Festival had one sign-up table, a few hundred intrepid souls, and a handful of enthusiastic volunteers.