This seems like a "borderline" question to me.
This is a travelling, not a "coach surfing" or "culture" site. So if you are talking about "visiting" far away places by viewing documentaries, that's not quite on topic.
What you need to do is to coach your question in terms of a trip that you actually PLAN to make. Then you can say, I'm planning to visit [Place X] in [Y months'] time; could you recommend any documentaries that will help me prepare for my upcoming trip. Even here, you ought to be " more specific" about what you want to "bone up" on; urban vs. rural sites, ancient vs. modern sites, etc.