What is "finswimming"

n. An underwater sport involving swimming with the use of fins.

Finswimming is an underwater sport consisting of four techniques involving swimming with the use of fins either on the water's surface using a snorkel with either monofins or bifins (i.e. one fin for each foot) or underwater with monofin either by holding one's breath or using open circuit scuba diving equipment. Events exist over distances similar to swimming competitions for both swimming pool and open water venues. Competition at world and continental level is organised by the Confédération Mondiale des Activités Subaquatiques (CMAS). The sport's first world championship was held in 1976. It also has been featured at the World Games as a trend sport since 1981 and was demonstrated at the 2015 European Games in June 2015.