Europeana is a website that provides access to millions of books, paintings, films, museum objects and archival records that have been digitised throughout Europe.
It includes a number of specific exhibitions. Two of these are about wars; the First World War and the Napoleonic War.
Untold Stories of the First World War contains photos, sound recordings, postcards, official documents and diaries; the last named are very big files. Most items relate to ordinary people, but there is a postcard sent by Adolf Hitler. It can best be explored from this link.
More items are being collected, and a series of First World War family history roadshows are being held across Europe. Click here for more information on roadshows and on how to contribute.
The Napoleonic War exhibition is hosted in conjunction with the European Library Exhibitions. It contains paintings, both battle scenes and portraits, maps and documents.