For the past 29 years, Matthew O'Sullivan has been working to fill in the gaps of New Zealand's military history.
He's the official 'keeper of photographs' at the Air Force Museum in Christchurch, which is home to an archive containing more than one million snapshots - documenting both the Air force and Defence Force over the years.
Some images date back to World War II, and a handful of negatives even go right back to the 1920s.
As well as conserving the collection, Matthew often gets requests from the public hoping to track down images of long-lost relatives, or from far-away towns who want to memorialise our country's role in the war.
Matthew O'Sullivan speaks with Susie Ferguson.