Albie Hay’s review published on Letterboxd :
It may not have been such a good idea to use Cave of Forgotten Dreams as a launchpad into the documentaries of Werner Herzog. The documentaries I tend to like centre on people, periods of history and ideas, so a documentary about some cave paintings isn't one I'd instinctively go for, but having been impressed by the Herzog I'd already seen I was hoping for an application of his distinctively dark slant on things.
We're told that in some caves along the bank of the Ardèche river in France are the oldest paintings known to man, which have been perfectly preserved for tens of thousands of years, concealed behind a wall of rock that indicates a landslide. Herzog has gained special permission from the French government to film inside the caves, and as he journeys inside with a film crew and a group of research scientists, we are presented with a collection of paintings that are astonishing merely for the fact that they could have survived, as well as for the insight into prehistoric man that they offer. Interviews with the scientists allow us to learn how the paintings have survived, what they tell us, and how they represent the lifestyle from which they are a relic.
The film is stunningly photographed, which shouldn't be too much of a surprise. But what also isn't a surprise is the difficulty Herzog seems to have in conveying a message. Why has he chosen to film these paintings aside from to be able to say he's gone where no one else has? Some narration at the end tries to link everything together, but Herzog appears to be too fascinated by the fact that there's a nuclear power plant nearby for a distinct idea to emerge, and we sense it's hard for him to be truly interested in the paintings, beautiful as they are. But because the film is so beautiful and informative, nothing much matters.