1. The Ascent of Man (1973)

Number one . . . absolutely numero uno. For my mind, the best documentary ever made. Of any genre.
In Ascent, Jocob Bronowski lays out the development of human society and its understanding of science in an amazing series of programs.
In the late 1960’s the fledgling BBC2 television channel wanted to set itself apart from either BBC 1 or ITV. Its new Controller, a certain David Attenborough (yes THAT David Attenborough!) started marking out a place for BBC2 with the acclaimed documentary Civilisation with Kenneth Clarke, a 13 part series on the role of art in Western European culture (a terrific doco in its own right). This was to be followed by a doco on the history of science, but that doco – Ascent of Man – took so long to organise and film, that a third commissioned doco from BBC 2 was released second. That doco was another acclaimed piece – America with Alistair Cooke.
Not a bad day’s work for Mr Attenborough, getting three acclaimed documentaries commissioned.
All three are great examples of the ‘talking head’ documentary, where a single narrator carries the show and the vision is used to back the narrative. However, Ascent stands out for me as the best example of the type. It was the most expensive documentary made at the time, as crews covered 27 countries to get the required shots, and it included some of the first computer graphics ever seen on TV.
But Ascent stands out because, unlike Civilisation where you could poke a stick at whatever you were talking about (architecture, sculpture, paintings), Ascent dealt with concepts and theories. Both Bronowski and the BBC put a lot of thought (and money) into what visual devices to use to get the message across. However, it is Bronowski that dominates the screen, and his delivery, which initially can be grating, generally draws you in.
Ascent first aired in 1973, and, sadly, just over a year later Bronowski died of a heart attack
If you want a devastating rebuttal to the IDiots and their IDiotic film Expelled, watch this – the end of part 11 Knowledge and Certainty
A simply must see documentary series for anyone with even a passing interest in science.
2. Life on Earth (1979)
David Attenborough again! This time in front of the camera. This excellent series stands out for the exceptional photography, and represents a shift in documentary making away from the ‘talking head’ towards the moving image as the main ‘hook’ with the narration (and narrator) there to support and explain the imagery. The first episode of Life on Earth ends in the Flinders Ranges of South Australia, with a shot of David Attenborough below some spectacular Ediacaran fossils (so I’m biased!)
The series is also famous for a sequence with Attenborough and some mountain gorillas.
3. The Civil War (1990)
What!? A Ken Burns documentary? Well, yes, the format has probably been overdone now, but The Civil War remains one of the earliest and best of what was another shift in documentary making, using archival footage, stills and multiple commentary from eye witness accounts, rather than the moving image. Or rather using film techniques to add movement to still images.