Initially predicting an Allied invasion at Normandy, Hitler changed his mind by the time of the attack and he hesitated to send support believing the assault there a diversion and the real one would be at Pas-de-Calais. Looking at the map, why did Hitler think Calais the best location for invasion?

The reason Germany chose to double-down Nazi defenses along the Calais coast was not only because of its proximity to England, but because Hitler fell hook, line and sinker for Operation Fortitude, one of the most successful military deception schemes in history. The Allies created a “dummy army” called the First U.S. Army Group (FUSAG) commanded by none other than Lt. General George Patton. When German spy planes made runs over Southeast England, they saw what looked like the buildup of a massive invasion force. But the regiments of tanks and landing craft were mostly inflatable decoys. Meanwhile, nearly every German spy in England had been either captured or turned into double agents. Those same agents told their Nazi handlers that the invasion was indeed planned for Calais, which was confirmed by phony Allied radio traffic intended to fall into German hands.

Explanation:

these civilizations were located around fertile rivers, where they could produce an abundance of crops