Jimmy Wales and Larry Sanger founded the collaborative website Wikipedia in 2001.
Wikipedia was first developed to become to a complement to an english-language encyclopedia called Nupedia.
It is a non-profit organization and it comprises more than 20 million articles, edited by collaborators all over the world in 282 languages.
The Wikipedia is sometimes criticized as not an absolutely reliable and accurate source of information, although an investigation carried by the magazine Nature stated that its level of accuracy level of error is equal to the Encyclopædia Brittanica.
It is one of the most visited websites with an estimate of 408 million unique users per month.