BFI reveals 'greatest documentaries of all time'
1 August 2014 Last updated at 12:20 BST
A silent movie from 1929 has been named the greatest documentary of all time by the British Film Institute's Sight and Sound magazine.
Man with a Movie Camera was chosen after votes from 100 critics and filmmakers.
Award-winning documentary-maker Sophie Fiennes and Sight and Sound magazine web editor Nick Bradshaw discuss the results.
First broadcast on BBC Radio 4's Today programme on Friday 1 August.