Wow, this is great. I watched your video on Exploring Czech Republic's Mining Heritage in Ostrava, and it was almost perfect. I loved the camera quality, despite inside the mines the quality was still great.

The only adjustment I will advise is the full use of subtitle. I noticed that sometimes you used used subtitles when the mine instructor was giving the history of the mine, especially when he was not too audible, but some other times there was no subtitles, and hence it required straining of the ear to hear what he was saying. Most of the things he was saying were juicy historical information, and the use of subtitles would have aided the better understanding of those historical facts.

I will advise that future videos have full subtitles of all that is said in them, so that people can get a full understanding of what is being said.

Apart from this, I would say (just like commenter @reseller said), the vlog was surely a masterpiece.