August 20 then

On this day in 1940 Leon Trotsky was struck down in his home in Mexico City by an assassin sent by Stalin. He died the following day.

On the same day in 1866 'the newly organized National Labor Union called on Congress to mandate an eight-hour workday'; and in 1968 the Soviet Union and other Warsaw Pact countries invaded Czechoslovakia.

On a somewhat different note, on this day in 1993 I saw István Szabó's movie Sweet Emma Dear Böbe. How do I know that that's when I saw it? I know, believe me. Let me tell you something about this movie that you almost certainly won't be aware of. Emma and her friend are walking along a city street and stop before the window of a bookshop. They see a book about Rosa Luxemburg. 'Rosa Luxemburg. Who's that?' asks Emma's friend. 'A revolutionary, I think,' Emma replies. The book? This one. See. In a movie. On August 20 1993.