In half an hour you see all of the men's family trees growing over 136 years, mixed in with photos of their families and historical time markers, with contemporary music, and with the cycles of the moon and the seasons. There are also sounds that connect in to the family trees (e.g. babies' cries signify births and the appearance of new branches on the trees).
The short segment below shows the few years just before the First World War up until the time the Group Photograph was taken. When you see the film from the very beginning in 1864 up until the turn of the Millennium in 2000, you get a picture of the First World War and its place within family lifetimes.
(NOTE: The actual film is in High Definition and needs to be viewed on a big screen to be able to fully appreciate the detail - what follows is a low resolution version that just gives the gist of what it's about).