As a frequent watcher of nature programs over the last 30 years, I have to say that this is one of the all time greats. Attenborough docs are always solid and there's no shortage of the usual charm, but the filming techniques have really come to the fore on this effort. There are utterly spectacular moments in each of the episodes. Yes, the overview episode is redundant, but there's very little else to be critical about. One for the ages, this.