A collection of tens of thousands of photographs by Kiwi photographer and photojournalist Olaf Petersen is one of five new additions to the New Zealand Memory of the World Register. Most of Olaf's 50-thousand photographs - give or take - were taken between the 1930s to the 1980s. Many are of Auckland's West Coast beaches and birdlife over that time. The Auckland War Memorial Museum's Pictorial Curator Shaun Higgins knows the collection better than most. In fact he's writing a book about Olaf Peterson whom he sees as Aotearoa New Zealand's pre-eminent 20th century nature photographer. Lynn Freeman asks Shaun why it matters so much to have Olaf's collection inscribed on the UNESCO-New Zealand Memory of the World Register.