Max Pearson presents a collection of the week's Witness History interviews from the BBC World Service.

The expert guest is Dr Mirjam Brusius, a research fellow in colonial and global history at the German Historical Institute.

First, we hear about Martín Chambi - Peru's pioneering documentary photographer.

Then Amaize Ojeikere talks about his father, JD 'Okhai’ Ojeikere, who created an iconic collection revealing the elaborate ways African women styled their hair.

Plus, the story of Magnum Photos – the picture agency started up by World War Two photographers.

And, Vivian Maier, the nanny who - since her death - has been hailed as one of the best street photographers of the 20th century.

Finally, the mystery behind Lunch Atop a Skyscraper – the famous photograph showing 11 ironworkers eating lunch nearly 70 storeys high.

Contributors:

Roberto Chambi – grandson of photographer Martín Chambi

This programme has been updated since the original broadcast.

(Photo: Two books of photographs in the exhibition 'Martin Chambi and his contemporaries’. Credit: Getty Images)