Today is Yom HaShoah. Amongst the several million Jews murdered by the Nazis some two hundred were deported from Venice to the death camps in Poland on 5th December 1943 and 17 August 1944. In the ancient ghetto of Venice - the original ghetto - there is a memorial plaque on which the following lines appear:
And nothing shall purge your deaths from our memories
For our memories are your only grave.
Here is one of the very first accounts of the death camp at Treblinka:
[T]here were periods when as many as 20,000 people were gassed in one day.