A sport is said to be an extreme sport when its practice involves serious risks of injury or even death. But this was really true several years ago, and nowadays, there is no accurate criteria to define an extreme sport, and therefore, this name comprises far more sports than it used to.

During the 70's and 80's, the only sports considered as extreme were the sports involving true risks of death, and from the 90's many disciplines declared themselves as extreme sports, probably to entice a new kind of athletes.

Nowadays, extreme sports are not all dangerous, even though there are still some risks. Some sports considered as extreme, are actually varieties of former sports involving just a little bit more technique, speed or height.

Among the most famous extreme sports, we can quote base jumping, which is considered as the most extreme of all the sports. Base jumping consists in jumping from a relief, stay as long as possible in free fall, and open a parachute as late as possible. Hence there is a true risk of death in case of error.

Extreme sports events are organized and usually gather the different sports according to the field they are practiced on. The X-Games, the Extremity Games and the Gravity Games are three most famous extreme sport events.