Wikipedia's editions when combined, comprise more than 61 million articles, attracting around 2 billion unique device visits per month and more than 15 million edits per month (about 5.8 edits per second on average) as of July 2023. Initially only available in English, editions in other languages were quickly developed. Founded by Jimmy Wales and Larry Sanger on January 15, 2001, it is hosted by the Wikimedia Foundation, an American nonprofit organization. Wikipedia is the largest and most-read reference work in history, has consistently been one of the 10 most popular websites, and as of 2023 ranks as the 4th most viewed website by Semrush. Wikipedia is a free-content online encyclopedia written and maintained by a community of volunteers, collectively known as Wikipedians, through open collaboration and using a wiki-based editing system called MediaWiki. Most text is also dual-licensed under GFDL media licensing varies