Here’s a short documentary film directed by Oskar Barnack (father of 35mm photography and inventor of the Leica camera) showing the workings of the factory where the first Leica cameras were made. The film includes footage showing the assembly of the Leica 1, produced between 1925 and 1932.
(via Leica Rumors)
P.S. Did you know Leica stands for Leitz camera, named after the founder Ernst Leitz?