Paper Clips (2004)

Middle schoolers in small-town Whitwell, Tennessee, set out to collect six million paper clips to grasp the number of Jewish victims of the Holocaust, and ended up housing them in a real German railcar. Because the story is told through kids close to the viewers' own age, it is one of the gentlest ways to introduce the Holocaust to a ten-year-old. It is rated G in the US and avoids graphic detail, but the survivors' accounts are moving and some descriptions of what happened are upsetting. Expect questions afterward, which is the point.