Orienteering originated in Scandinavia in the late 19th century and the first international competition was held in Norway in 1932. It has since spread around the world with the International Orienteering Federation established in 1961 and now having 67 member countries. Some of the largest orienteering events include O-Ringen in Sweden, which has been held annually since 1965, and the Jukola Relay which has attracted over 1300 teams from 25 countries. Orienteering involves navigating through unfamiliar terrain using a specially designed map to locate control points. Competitions have different formats including individual, relay, sprint and night races. There are also variants like MTBO which uses mountain bikes and ski orienteering.