Despite the name, polo is almost never played at the Polo Fields in Golden Gate Park. The multi-purpose sport field, which is made up of six soccer fields surrounded by a track nearly three quarters of a mile long (1 kilometer), was originally called Golden Gate Park Stadium and opened in 1906 as a track cycling arena. It was the home field of San Francisco rugby teams of the Northern California Rugby Football Union during the 1960s and 1970s. The field is used for soccer games, running, horse riding, cycling, and plays host to concerts and annual music festivals. The Bay to Breakers post-race party and Outside Lands Music Festival are held at the fields.