Finswimming is an individual sport, that uses a large "mono fin" to propel the swimmer through the water. The swimmer can reach high speeds, which makes these races faster and more exciting than conventional swimming races.
The history of finswimming goes back to 1927, where a Lt. Collier from France tried out a dolphin shaped fin to acheive higher swimming speeds. This fin was replaced in the early 70's by the currant "mono fin", which is composed of fiberglass, or carbonfibre. The swimmer also wears a mask.
There are many disiplines involved in finswimming, some of which include surface swimming of distances from 25m to 1500m; apnea - where the swimmer is completely submerged and holding their breath, for distances from 25m to 50m; and immersion events of 100m, 400m & 800m, where the swimmer is submerged and has a pony bottle of air to breathe off of. Finswimming events take place in swimming pools and open water. CMAS, the World Diving Federation, is the organizing body for Finswimming. The sport is not as popular in North America, but has a large following in Europe, Asia, and South America.