I met this website some weeks ago and I think it is one of my favorite ones. In this website you can watch courses of lots of famous universities, like harvard, MIT, standford and hundreds of more free. You just have to pay if you want a certificate that explains that you did the course.
You can find courses of everithing, most of them in english, but they are also in spanish available. If you don't understand english so well, there are also subtitles.
You can register here: https://www.coursera.org/
Well, i wont stop you longer, lets learn!