Finding Long and interesting articles online, HOW?

I want to read alot on various topics.. I've tried sites like ociatedcontent.com , a rticlebase.com, articlebiz.com, etc. And they are nice. ociatedcontent is the best i found so far, but sometimes i can't find stuff and sometimes the articles are really small. Where can i find more LONG articles which are fun and interesting..like talk about Humanoid robots in japan, History of chocolate, History of aztecs... etc, Discrimination in the work place, etc etc. Long and interesting articles.. any help?