There are hundred if not thousands of sites with sources and document about WWI - from local over regional to just special events.
, a project based at the University of Oxford, hosts a remarkable collection of primary documents relating to World War I, collected by individuals, libraries, and film archives across Europe.
Hundreds of letters, diaries, photographs, World War I films, official documents, and postcards are to be found there. Each resource type is further sorted by subject (Propaganda, Women, Aerial Warfare, etc.) or front (Italian Front, Home Front, Eastern Front, and Western Front), letting visitors explore the experiences and perspectives of European, American, Australian, and New Zealand soldiers.
Europeana 1914-1918 – untold stories & official histories of WW1