Radical slideshows from the 1920s

Anarcho-syndicalist, communist, Trotskyist and adult educator Henry Sara put together an archive of over 1500 "lantern" slides in the 1920s and 1930s which he used to illustrate his talks on things like the Easter Rising in Ireland, spiritualism, the 1926 general strike, the Chinese revolution of 1927 and the history of the British labour movement. They've been digitised and can be viewed online here - an amazing resource.