Today is one of the most somber points in the Israeli calendar, when sirens call the nation for two minutes silence to mark those killed in the Holocaust. The day is a moment to reflect on the continuing research into the Nazi plan to exterminate the Jewish population of Europe. This year has seen the opening of an exhibition dedicated to the young men who ran a football league in the ghetto of Thersienstadt in the Czech Republic. This was a ghetto the Germans used to try to deceive the world about the Holocaust, where they fooled visiting Red Cross inspectors and even shot a propaganda film. Kevin Connolly is from our partner the BBC.