The Exploits of the Emden (1928)
The Exploits of the Emden is a 1928 silent Australian film about the Battle of Cocos; the World War I naval battle between Australian cruiser and German cruiser . It consists of footage from a 1926 German film, Unsere Emden, with additional sequences shot in Australia by director Ken G. Hall. Only part of the film survives today.
More at Wikipedia.