In 1938, you have what is known as Kristallnacht or the Night of Broken Glass. Hundreds of synagogues are burned, thousands of Jewish businesses are destroyed, and many Jews are killed in that night. Then as we get into 1939, Hitler's armies famously invade Poland, beginning what many historians consider to be the start of World War II. What would eventually be known as the Holocaust goes into full effect in 1941. Jews are sometimes executed in the streets, in their homes. Many of them are captured and sent to concentration camps. To get a sense of the scale of this operation, we have this excerpt from Michael Barenbaum's book, The World Must Know.