The photo below shows Soviet Jews in trenches being shot by the Einsatzgruppen (German Death Squads). Hitler was a creative artist, the author of the Final Solution. He set things up the way he wanted things to happen

The trenches in the Soviet Union replicated the trenches of the First World War.  Now at last, 27 years after Hitler's traumatic experience he would enact revenge. But instead of German soldiers, it would be Jews--helpless, shot and slaughtered in trenches. Jews in the Soviet trenches symbolized German soldiers slaughtered in trenches during the First World War.

Finally, pay-back time:  "Do unto others as had been done unto you."

Photo of the Einsatzgruppen murdering Jews in the Soviet Union.