The Wikipedia is awesome. It's an online encyclopeda that anyone can contribute to. I have contributed to about 300 articles, some of which are minor typos or grammar corrections, some of which is reverting vandalism, but most are significant contributions to the article text, or images added to articles.
You do have to be careful with using Wikipedia, because there are vandals and trolls that deliberately try to destroy or distort the content, but overall it's a very useful resource.
There are many different language versions, and links from articles to the versions in other languages, and I encourage anyone with good language skills to contribute translations from your secondary language to your primary language's encyclopedia.