Ski jumping has been included at the Winter Olympics since 1924 and at the FIS Nordic World Ski Championships since 1925. Women's participation in the sport began in the 1990s, while the first women's event at the Olympics has been held in 2014. All major ski jumping competitions are organised by the International Ski Federation. Stefan Kraft holds the official record for the world's longest ski jump with , set on the ski flying hill in Vikersund in 2017. Ski jumping can also be performed in the summer on an in-run where the tracks are made from porcelain and the grass on the slope is covered with water-soaked plastic. The highest level summer competition is the FIS Ski Jumping Grand Prix, contested since 1994.