Answer
Nazi Germany's persecution and systematic extermination of Jews, known as the Holocaust, posed the primary threat to the children whose lives Sir Nicholas Winton tirelessly worked to save. During the late 1930s and early 1940s, Winton organized the rescue and safe passage of over 669 predominantly Jewish children from Nazi-occupied Czechoslovakia to the United Kingdom, giving them a chance to escape the horrors of impending genocide and find refuge.