By 1938, the Nazis had been in power for five years and were trying to make Germany "Judenfrei" (Jew free). On October 28th, 1938, the Gestapo (Nazi secret police) rounded up Polish Jews in Germany and sent them back to Poland. With little food, water, and no shelter in the middle of winter, thousands of Jews died.
Among those Polish jews were the parents of Herschel Grynszpan. As an act of anger against the Germans, he shot Ernst vom Rath, the third secretary in the German embassy in Paris.
The day Ernst vom Rath died, on November 9th, 1938, Nazi Propaganda Minister Joseph Goebbels announced a government-sanctioned attack against the Jews. They ravaged synagogues and burned them. Jewish shops were destroyed, and many jews were beaten, raped, arrested, and murdered.
Police and firefighters stood idly by during the destruction of Jewish buildings, only taking action to prevent the spread of fire to non-Jewish buildings. 91 Jews were killed, and 30,000 Jews were sent to concentration camps.
NOTE:
Kristallnacht means "Crystal Night" or "Night of the Broken Glass"