Wikipedia is a multilingual online encyclopedia created and maintained as an open collaboration project by a community of volunteer editors. It is the largest and most popular general reference work on the internet and is one of the 20 most popular websites as of March 2020. It features exclusively free content and no commercial ads, and is owned and supported by the Wikimedia Foundation, a non-profit organization funded primarily through donations.
Wikipedia was launched on January 15, 2001, by Jimmy Wales and Larry Sanger. Initially an English-language encyclopedia, versions of Wikipedia in other languages were quickly developed. With 6.1 million articles, the English Wikipedia is the largest of the more than 300 Wikipedia encyclopedias. Overall, Wikipedia comprises more than 52 million articles attracting 1.5 billion unique visitors per month.