Slowly but surely we're closing the book on our links to the early 20th century. The last survivor of the Titanic is now gone, and in the United States, there is a sole survivor of the American Expeditionary Force that went to France in 1917. If I recall correctly, the last Australian veteran of World War I died a few years ago. Not sure if there are any veterans of either the Kaiser's army or the Tsar's army still alive.
Consider too that technology we take for granted is rapidly approaching the century mark: the Model T Ford celebrated a centennial last year; self-starters in cars are closing in on a century in (I believe) the next two years; commercially viable radio will hit a centennial in 2015, if I recall correctly (although commercial radio itself did not become a reality until 1920).