On Wednesday, it’s Holocaust Memorial Day. Every year it reminds us of the vital duty not just to remember past tragedies, but also to examine carefully the world as it is today. Last year, I was privileged to work on a BBC documentary called My Family, The Holocaust and Me. The mission of the programme was to shed some light on the individual stories and humanity of just some of the many millions who were murdered. But it also tried to sound a warning that we must never become complacent: the Holocaust happened in a recognisably modern world to people with lives like our own. It really just takes a handful of apparently unrelated economic or political switches to flip, and even the most civilised, enlightened world can descend into atrocity. It can happen anywhere and at any time — Holocaust Memorial Day tries to keep us learning this lesson every year.