For the past few months, Margarete Kraus’s face has been looking out at passengers in the lifts at Russell Square tube station. Photographed in the 1960s, she is leaning from the window of her caravan, smiling. Her Auschwitz prisoner number is tattooed on her left forearm. Kraus, who came from Czechoslovakia, was one of the hundreds of thousands of Roma and Sinti people targeted by the Nazis for extermination in the 1940s. Her story is told, alongside those of others, by an exhibition at the Wiener Holocaust Library.