Wikipedia

http://www.wikipedia.org/

Wikipedia is a Web-based, free-content encyclopedia, which is written collaboratively by volunteers. It consists of 195 independent language editions sponsored by the non-profit Wikimedia Foundation. Entries on traditional encyclopedic topics exist alongside those on almanac, gazetteer and current events topics. Its purpose is to create and distribute, worldwide, a free encyclopedia in as many languages as possible. Wikipedia is one of the most popular reference sites on the Web, receiving around 50 million hits per day.