Wikipedia!
“Wikipedia is a Web-based free content encyclopedia designed to be read and edited by anyone, with editions of varying sizes in 190 languages. 16,000 registered users collaboratively edit and maintain the English edition Wikipedia, which has allowed it in less than four years of operation to become the world’s largest encyclopedia, containing 460,000 articles (growing 3000 per day) and 77 million words. In all language editions combined, Wikipedia contains over 1.3 million articles.” (From the website)
I love this site. Check it out if you want to inform yourself!