Probably www.history.extra.com is a wonderful site, but in the free trail I discovered I was not able to understand the video's because of the lack of subtitles. So at the same day I started the free trail I ended it the way I was told in the welcome mail.
Now four months later I see my credit card is charged monthly for the abonnement.
Follow up: Eventually History.com responded to my emails in a very elegant way. They apologized sincerely and gave a fully refund. And an offer for a year free membership (I won't use this offer, because my understanding of spoken English is not good enough and there are no subtitles, but I appreciate the offer)