To prepare for the eventuality of an Allied attack, the Germans built a system of fortifications along the entire western coast of the territory they had occupied. These fortifications extended from the north of Norway, by way of Denmark, the Netherlands and Belgium, to the Spanish border in southwest France.
The Atlantic Wall consisted of a large number of bunkers with anti-aircraft guns, obstacles and anti-tank ditches. In the Netherlands it was above all the strategically important ports of IJmuiden, Hook of Holland and Vlissingen that were heavily defended. The population of coastal areas was evacuated.
For more information, see the website Atlantik Wall in the Netherlands.