Alarmed by the raids on St Nazaire and Dieppe in 1942, Hitler had ordered the construction of fortifications all along the Atlantic coast, from Spain to Norway, to protect against an expected Allied invasion.
He envisioned 15,000 emplacements manned by 300,000 troops, but shortages, particularly of concrete and manpower, meant that most of the strongpoints were never built.
As it was expected to be the site of the invasion, the Pas de Calais was heavily defended.
In the Normandy area, the best fortifications were concentrated at the port facilities at Cherbourg and Saint-Malo.
Rommel was assigned to oversee the construction of further fortifications along the expected invasion front, which stretched from the Netherlands to Cherbourg, and was given command of the newly re-formed Army Group B, which included the 7th Army, the 15th Army, and the forces guarding the Netherlands.
Reserves for this group included the 2nd, 21st, and 116th Panzer divisions.

Rommel believed that the Normandy coast could be a possible landing point for the invasion, so he ordered the construction of extensive defensive works along that shore.
In addition to concrete gun emplacements at strategic points along the coast, he ordered wooden stakes, metal tripods, mines, and large anti-tank obstacles to be placed on the beaches to delay the approach of landing craft and impede the movement of tanks.
Expecting the Allies to land at high tide so that the infantry would spend less time exposed on the beach, he ordered many of these obstacles to be placed at the high water mark.
Tangles of barbed wire, booby traps, and the removal of ground cover made the approach hazardous for infantry.
On Rommel's order, the number of mines along the coast was tripled.
The Allied air offensive over Germany had crippled the Luftwaffe and established air supremacy over western Europe, so Rommel knew he could not expect effective air support.
The Luftwaffe could muster only 815 aircraft over Normandy in comparison to the Allies' 9,543.
Rommel arranged for booby-trapped stakes known as Rommelspargel (Rommel's asparagus) to be installed in meadows and fields to deter airborne landings.


Nazi armaments minister Albert Speer notes in his 1969 autobiography that the German high command, concerned about the susceptibility of the airports and port facilities along the North Sea coast, held a conference on 6–8 June 1944 to discuss reinforcing defenses in that area.
Speer wrote: 
In Germany itself we scarcely had any troop units at our disposal.
If the airports at Hamburg and Bremen could be taken by parachute units and the ports of these cities seized by small forces, invasion armies debarking from ships would, I feared, meet no resistance and would be occupying Berlin and all of Germany within a few days.
Alarmed by the raids on St Nazaire and Dieppe in 1942, Hitler had ordered the construction of fortifications all along the Atlantic coast, from Spain to Norway, to protect against an expected Allied invasion. He envisioned 15,000 emplacements manned by 300,000 troops, but shortages, particularly of concrete and manpower, meant that most of the strongpoints were never built. As it was expected to be the site of the invasion, the Pas de Calais was heavily defended. In the Normandy area, the best fortifications were concentrated at the port facilities at Cherbourg and Saint-Malo. Rommel was assigned to oversee the construction of further fortifications along the expected invasion front, which stretched from the Netherlands to Cherbourg, and was given command of the newly re-formed Army Group B, which included the 7th Army, the 15th Army, and the forces guarding the Netherlands. Reserves for this group included the 2nd, 21st, and 116th Panzer divisions.
Rommel believed that the Normandy coast could be a possible landing point for the invasion, so he ordered the construction of extensive defensive works along that shore. In addition to concrete gun emplacements at strategic points along the coast, he ordered wooden stakes, metal tripods, mines, and large anti-tank obstacles to be placed on the beaches to delay the approach of landing craft and impede the movement of tanks. Expecting the Allies to land at high tide so that the infantry would spend less time exposed on the beach, he ordered many of these obstacles to be placed at the high water mark. Tangles of barbed wire, booby traps, and the removal of ground cover made the approach hazardous for infantry. On Rommel's order, the number of mines along the coast was tripled. The Allied air offensive over Germany had crippled the Luftwaffe and established air supremacy over western Europe, so Rommel knew he could not expect effective air support. The Luftwaffe could muster only 815 aircraft over Normandy in comparison to the Allies' 9,543. Rommel arranged for booby-trapped stakes known as Rommelspargel (Rommel's asparagus) to be installed in meadows and fields to deter airborne landings.

Nazi armaments minister Albert Speer notes in his 1969 autobiography that the German high command, concerned about the susceptibility of the airports and port facilities along the North Sea coast, held a conference on 6–8 June 1944 to discuss reinforcing defenses in that area. Speer wrote: 
In Germany itself we scarcely had any troop units at our disposal. If the airports at Hamburg and Bremen could be taken by parachute units and the ports of these cities seized by small forces, invasion armies debarking from ships would, I feared, meet no resistance and would be occupying Berlin and all of Germany within a few days.
Normandy landings