The world of sports is an exceptionally rich tapestry, and whilst the attention of the most popular athletes in their elite sports clothing is concentrated on conventionally popular sports such as football and athletics, other, less common sports have rocketed in popularity.
The most notable example of this was the sport of Mixed Martial Arts, which evolved from a series of disconnected events, film plots, strange one-offs and accusations of being a bloodsport into one of the biggest combat sports in the world in the span of three decades.
Thanks to the rise of cable television and later online distribution, a wide range of unique, complex and esoteric sports have evolved from fringe events to professional sports. Here are some of the strangest.
After several adaptations of the rules and a schism as to how seriously the sport should be taken, chess boxing evolved into the rules it is known for today, with 11 three-minute rounds, five of which are boxing and six of which are part of a nine-minute blitz chess game.
It has become hugely popular because of the extremes of skills involved, with two different governing bodies with particularly different philosophies.
One of the oldest Olympic events and yet in practice one of the oddest, race walking is the sport of competitive fast walking.
On the face of it, this does not seem like a strange event, especially considering how many long-distance running events are played at an Olympic level.
What makes this much stranger, however, is the rules that are designed to stop people from running. One foot must be visibly on the ground at both times and a race can never bend their knees, which is penalised with a three-faults system. Bend your knees too much three times and you are disqualified.
So unique and obscure it is as a sport that when it was parodied in the early 2000s many people assumed it had been made up.
After the popularity of MMA surged forward, other sports have risen to try and become another combat sports juggernaut, but whilst the likes of XARM have become lost media, one sport that has become increasingly popular and controversial is slap-fighting.
The reasons for both are fairly self-evident, with slap-fighting being a three-round contest of two opponents slapping each other really hard in the face, and if one cannot get up after 30 seconds, they lose.
This brevity and visceral aspect have given it many supporters, but at the same time, the fact that any form of defence is against the rules (unlikely literally any other form of combat sport) has granted it controversy.
With that said, given that UFC president Dana White has launched a slap-fighting league, the sport is at a crossroads where the increased publicity will make it even bigger, or the scrutiny surrounding it will stop the burgeoning league in its tracks