Wikipedia
Tiomila
Tiomila or 10-mila is an orienteering race held annually in Sweden since 1945, usually in late April or early May. It is a 10-man relay which includes both night and daytime legs. The women's race consists of five daylight legs. Tiomila attracts club teams from all the major orienteering nations. In 2008, both the men's and the women's race consisted of about 350 teams. In 2010, there were 361 women's teams, and 359 men's teams.
The name means "ten [[Norwegian/Swedish mil|[Swedish] miles]]" (100 km) and refers to the total distance run by each team. The actual distance however varies from year to year. The 2015 edition was measured to along the straight line between the controls.