100 years since the Russian Revolution, Imperial Russia in colour, AIDS and the mystery of 'Patient Zero', when Indian sex workers marched for employment rights and the British Lord who fled the Nazis in Czechoslovakia as a six year old on the Kindertransport.

Photo: 12th March 1917: Barricades across a street in St Petersburg, as a red flag floats above the cannons, during the Russian Revolution. (Photo by Hulton Archive/Getty Images)