This site from the National Library of Canada lets you see and hear music of the First World War era. Sheet Music in Canada is a searchable database of about 400 pieces of sheet music published in Canada between 1914 and 1918, including cover images, catalog descriptions, and scores (if copyright clearance has been obtained). Composer names, titles, subjects, and keywords can all be used as search terms; once a search has been executed and a description displayed, names and subjects are hyperlinked so that users can easily find more related music.