German WW1 & WW2 fortifications in Denmark & Europe      
 
                     
      American infantry crossing the Siegfried line in February 1945      
 

The objective of a fortification
Throughout history, man has sought to claim ownership to selected parts of geography by fencing it off in one way or another. From the earliest days individuals and groups have thus marked their territory, chieftains have built castles, city dwellers have surrounded their houses with walls and peoples have defended their countries with border- and coastal fortifications. Marking ownership to territory and thus restricting access for others seem to be a fundamental urge for man.

Apart from marking the territory, the primary function of any fortification is deterrence. By its mere might and force, enemy forces should be rendered disheartened and refrain from attack or at least start this fearful and aware of their own inferiority.

Once in combat, the primary task shifts to protection; protecting observation, communication and weapons systems and their operators against hostile activity and thus preserve the battle worthiness of the position. The means to achieve these goals are partly active – the firepower installed – and passive in terms of the protection offered by buildings, excavations and camouflage.

Autonomy – the ability to function effectively for some time without supplies and reinforcements needed from the outside – is also an important parameter for any fortification.

Types of fortifications
A fortification can either be temporary or permanent. In military jargon, the words field fortifications and fixed fortifications are often used here. The field fortification is by nature improvised; tools and materials at hand are used, it is most likely crafted by untrained personnel using simple instructions as i.e. a field manual. It is erected to cater for fluctuating developments in the strategic theatre on the battlefield and the expected lifespan is short, sometimes just hours or days. Field type fortifications can, however, also be applied to supplement fixed fortifications.

Fixed fortifications on the other hand, are erected where you intend to stay permanently at least for a considerable time. The Atlantic Wall is an excellent example here, as we may assume that the Nazi Regime did not expect to man it for all times – only until England had surrendered and the world had yielded to the idea of a Europe under Nazi rule. Unlike the field fortification, the fixed is most often constructed by trained labor using heavy tools and machines, lots of concrete and steel and working from detailed drawings that may embrace plumbing and heating, electric installations and amenities such as baths, kitchen facilities and dormitories. The fixed fortification will provide protection against heavy shelling, bombing and the use of chemical warfare.

Prominent examples of the great fortifications built in the last century embrace the Maginot line in France, The Belgian fortress of Eben-Emael and the Siegfried Line in Germany.

The importance of camouflage
If you are hard to see, you are hard to hit. This simple truth has encouraged the use of camouflage throughout centuries of warfare. A deviation from this rule was the flamboyant uniforms of Europe’s renaissance armies, obviously created from a wish to display splendor in parades rather than from field-tactical considerations. The development of the accurate bolt-action rifle in the 19th century and later the machine gun soon put an end to the concept of marking the position of the heart with a white bandoleer.  

Camouflage is often mandatory in field fortifications, but even the large, bulky structures of the fixed fortification can benefit from concealment that serve to render the enemy uncertain of where exactly to aim. Thus, clever use of camouflage begin with studying the terrain and try to “blend in” when construction the fortification. This also allows for use of existing hindering elements such as waterways, soft or steep terrain, and natural gorges and crevasses.

German WW2 classifications
The demands to a fortification may vary from a small strongpoint to a huge fortress depending on the importance of the area and the forces that are likely to be applied on behalf of the enemy. The German Army (Wehrmacht) operated with five standard classifications:

1. Resistance nest (Wiederstandsnest)
This is the smallest unit, consisting of one group (10 men incl. a lance corporal) or maybe two or three. Heaviest weapons are machine guns and hand grenades. Typical tasks could be to observe enemy movements, protect an installation or an access road. The resistance nest typically embraced one or more crew bunkers (often R621/622) and special bunkers for e.g. artillery observation or machine guns. Some fifteen spots along the Danish Atlantic Wall were appointed Resistance Nests.

2. Strongpoint (Stützpunkt)
Two or more resistance nests constituted a strongpoint. Personnel strength close to that of a Company (approx. 100 men) armed with hand guns, heavy machine guns, mortars and anti-tank weapons. The Danish part of the Wall comprised 15 Strongpoints.  

3. Strongpoint group (Stützpunktgruppe)
A strongpoint group comprised several strongpoints under joint command up to Battalion strength. Examples of strongpoint groups are coastal batteries, radar installations and field-type airstrips. A strongpoint group could embrace bunkers for fire control, water supply, kitchen and dressing station along with gun embrasures. Armament could include heavy artillery, AA guns and anti-tank guns.
In Denmark Skagen, Frederikshavn, Thyborøn and Blåvandshuk were classified Strongpoint Groups.

4. Defense area (Verteidigungsbereich)
A defense area was a comprehensive facility, embracing a large area e.g. a garrison, a major airstrip or a whole city. Thus, a defense area was an autonomous entity consisting of several strongpoint groups and individual strongpoints. Civilian residential areas could also be part of the area. All types of bunkers could be included and the area most often comprised elaborate defensive constructions such as tank ditches, mine fields anti-tank positions at access roads and a generous use of Czech hedgehogs and barbed wire.  

Denmark comprised four Defense Areas; Aalborg, Hanstholm, Esbjerg and Grove (today: Karup) Air Base.

5. Fortress (Festung)
Fortress was the German name for a particularly large fortification that could comprise several independent defense areas. Also, in accordance with the Hitler Directive (Führerweisung 40 of March 23rd 1942), a Fortress could not be surrendered to the enemy, but had to be defended to the last man and the last bullet. As the German armies withdrew at the end of the war, Hitler saw it fit to appoint cities on the route of enemy advances “fortresses” in order to slow down the onslaught, especially of Russian forces.

Although large facilities such as Hanstholm, and Thyboron are sometimes referred to as fortresses in local terminology, no defense area in Denmark was ever appointed “Festung”.

Most common Regelbau bunkers in the Danish Atlantic Wall
A stroll along the Danish western coastline will quickly leave the impression that the Atlantic Wall mainly consisted of x type of bunkers; Regelbau 622 Crew Bunker, R671 Gun Emplacement and the prominent R636 Fire Control or Command bunker. With their forward placement, overlooking the sea and in most cases clearly visible from the beach the gun bunkers and the command bunker literally spell "Coastal Battery", but there are many more types concealed in the dunes and the trees behind.

To be further elaborated

Development in the the theatre of war
To concur and eventually seize an enemy fortification, military engineers and pioneers have displayed great ingenuity throughout times. Elaborate machinery has been devised to overcome e.g. the large castles of the medieval by use of ramrods, trebuchets and ballistae, or the wall could be climbed using long ladders. By these simple means, castles that a first glace seemed impregnable were overcome by invaders.  

The invention of rapid action firearms such as the machine gun seemed for a brief period to pin man down in trenches, unable to advance without staggering costs in human life, but the subsequent appearance of the tank (in essence a movable fortress) opened up the tactical situation once again and added to the perils of trench warfare. As a result, all continental parties that had suffered massively under the First World War took steps to protect their soldiers should war break out again. Mighty fortresses were erected along the French/German and Belgian/German borders, offering troops sanctuary under meters of concrete and steel.

At the outbreak of WW2 in the west in 1940, however, developments in weapons technology had expanded the threats to the fixed fortification tremendously – a bitter lesson learned by Belgium and France in the first weeks of war. The German Army (Wehrmacht) having learned from the horrors of the trenches now placed their emphasis on mobility, coordinated and massive use of air power and armored warfare and the use of paratroopers and glider-assaults. Thus, the still old-fashioned armies of the allies were no match and were quickly overrun. The mighty fortresses of Eben-Emael and the Maginot line were either subdued by flashing air assaults or simply by-passed.

Hitler was in no way the military mastermind some historians want to attribute him, but he did possess a political nose and he  was quick to adapt the idea of Blitzkrieg – Lightning Attacks with highly mobile forces – and he did score massive victories in the early years of WW2 with these tactics. In the view of this, it is fair to ask why the Führer himself just a few years later yielded to construct a fixed fortification of a magnitude as that of the Atlantic Wall. The answer is quite simple though; he had no other option. At that point in the war, the crumbling eastern front consumed all available resources and manpower, and to leave just a remote chance to fend off an attack in the west, the attackers had to be stopped on the beach – or not at all.

Field Marshal Erwin Rommel – the legendary “Desert Fox” and at that time one of Hitlers pet generals – was appointed to spearhead reinforcement of the Atlantic coast fortifications from Norway to Spain, and it is fair to say that he, given the conditions, did a tremendous job. Being an experienced tank commander he probably realized that all his efforts were in vane, but with little choice, he set out to saturate the 5000 km coastline with millions of mines, countless makeshift obstacles and some 15.000 Regelbau bunkers to counter the expected invasion of allied forces.

Air assault
Since the First World War the airplane had developed from a flimsy kite-like contraption into an awesome machine of destruction and as the new war progressed, this weapon established itself as the key factor in all modern warfare; the party that possess air supremacy will essentially also call the shots on the ground.  

Air assault was thus a major concern to Rommel's fortifications which has to be able to preserve the fighting ability of the soldiers after the heavy bombardment that would precede enemy landings. Thousand of bunkers of every sort were erected in record time and protected by anti-aircraft guns of every caliber. Coastal artillery was protected in concrete embrasures and ammunition stockpiled in deep bunkers. Crews lived, slept and ate under two meters of reinforced concrete and all vital components right down to the water supplies were entombed in bunkers.

Artillery assault
Heavy guns have been used in sieges since the Hundred Year War (actually 116 years; from 1337 to 1453), but had its peak during WW1 where massive barrages – sometime days long – preceded infantry attacks on enemy positions. Also during the Second World War artillery was used extensively, but heavy fortifications provided ample protection against most land-based artillery although trenches, telephone cables, barbed wire and field fortifications were likely to suffer destruction.

Naval artillery was another matter. Firstly because of its immense caliber with grenades that could be up to 42 cm in diameter and weigh more than a ton. Secondly because direct fire would be used, aimed at necessary embrasures, and finally because the battleship is a mobile enemy that can be difficult to hit by coastal batteries that even are inferior in firepower.

Armored assault
Also the tank was a brainchild of the Great War and rapidly developed from the slow steamroller of trench warfare to the powerful assault vehicle of WW2. Massive armor made it impregnable to common infantry weapons and mobility and firepower enabled it to penetrate deep behind enemy lines and raise havoc amongst unprotected soldiers. For a long period the military doctrine demanded that the only effective weapon against a tank was – another tank. However, development in weapons technology produced effective anti-tank guns such as the feared German “88” along with an array of man borne rocket launchers, comprising on the German side the “Panzerfaust” and “Panzerschreck” or with the allied, the American “Bazooka”. Very effective, cheap and highly feared by tank crews was the panzer mine, e.g. the German “Tellermine” that could easily destroy a tank.

Rommel put all this into use and supplemented with tank ditches, dragon teeth and Czech hedgehogs to canalize tank attacks into "killing zones" - areas and angles that were suitable for his anti-tank weapons.

Infantry assault
Air bombardments and shelling can initiate the attack and serve to stun the defenders and reduce their fighting power, but to force a surrender, you will most often have to deploy your own troops in a classic infantry assault that in its essence has not changed since the medieval wars. During the last great war however, the infantryman could rely on an array of weapons and gizmos to ease the job. It comprised special explosive charges, flame throwers, rocket propelled grenades and support from armored, specially designed vehicles (called "Hobarts Funnies") to overcome minefields, tank ditches and barbed wire.

The future fortress
The Atlantic Wall was one of the mightiest obstacles, man has ever built to to ward off an attack. It stretched from northern Norway to the Pyrenees and when it was finally assaulted, the attack came on one of the most heavily fortified areas (personally, I never understood why they didn't pick Denmark*). Nonetheless, after twelve hours the wall was penetrated, bridgeheads established and Fortress Europe had to join the league of monuments over yesterdays warfare. Many young men died in the ordeal, but it was still just a fraction of the deaths experienced during some of the infantry attacks of the first world war.

The Atlantic Wall is likely the last mighty fortification to be built for ages to come. Already before the work started, it was obsolete and not even its constructors seriously believed that it would hold back an invasion if and when it came. It was primarily a showpiece, conceived to boost the morale at the home front and deter the enemy from attempting to invade. As invasion became a reality, it took only hours to prove once again that a determined attacker with sufficient resources will always win the day.

           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
     

 

     
           
           
           
           
           
           
           
           
     

*Long, poorly defended coastline, second-rate complaisant troops in inferior numbers. Outdated artillery. Little and obsolete panzer.

Good infrastructure from beach landings to major roads. A straight road to Berlin with no rivers to cross. 

Closing off supply lines to Norway. Immediate access to the Baltic and German coast, the list goes on."

You tell me...

     
     
     
             
      This text will be further elaborated with Regelbau examples. Comments are welcome...