La Coupole, Saint Omer

Engineering behind Hitler's Atlantic Wall

Contrary to Nazi propaganda and despite some brilliant engineering, Hitler's 6000km 'Atlantic Wall' of coastal fortifications proved fairly ineffective from a strategic point of view. Seventy years after VE day, we visit some of the Wall's remaining sites in France.

I am walking along a sandy Cap Gris Nez beach near Calais, just centimetres from the softly murmuring surf. It is a bright sunny afternoon in April, and looking across the English Channel I can clearly see the White Cliffs of Dover 22 miles away.

These 22 miles have a personal significance for me: I will never forget my first Channel crossing as I fled the Soviet Union to find shelter and eventually a new home in the country of my dreams. For me as for so many other people - desperate refugees, idealistic travellers, failed invaders - it was the ultimate Rubicon, the crossing of which meant if not necessarily a new life, then definitely new impressions and new beginnings.

These few miles of white-capped sea can safely be called one of the most emotionally charged and fought-for stretches of water in human history. Staring at the hazy outlines of the White Cliffs of Dover from Calais is like taking a vicarious journey back in time.

It was here that Napoleon stopped in 1803 to contemplate the invasion of Britain. It was from here that Louis Bleriot started his historic cross-Channel flight in 1909. And on Christmas Eve 1940, Adolf Hitler came here to inspect the emerging fortifications of what he liked to refer to as 'Fortress Europe'.

By the end of 1940, it had become obvious to Hitler that the invasion of Britain was not practical, and - with the Russian campaign firmly in mind - he had already ordered the transfer of some of his troops from northern France to the east. At the same time, he wanted to retain the already occupied European territories and to keep harassing Britain from across the Channel. Almost a year to the day after his visit to Calais, Hitler started talking about an 'impregnable' line of defence stretching for 6000km along the Atlantic coast, from the Franco-Spanish border all the way to Scandinavia.

The words 'Atlantic Wall' were largely metaphorical: a propaganda-style soundbite to describe 15,600 concrete bunkers, gun batteries, turrets, tunnels, towers and emplacements, built along the coastline. With time, several V1 and V2 rocket factories, depots and launch sites were to be added to the Wall, mostly in Northern France, for use against Hitler's sworn enemy, Britain.

Organisation Todt

At the time of its conception, Hitler's Atlantic Wall idea did not go down very well with the hierarchy of the German military machine, the Wehrmacht. Many of his generals were worried that the bulky and costly fortifications (on French territory alone, they were to cost German taxpayers 2.7bn Reichsmarks) would divert essential engineering and manpower resources from other areas, where they were needed most.

There was no stopping Hitler, however, and on 23 March, 1942 he instructed Organisation Todt (Nazi Germany's civil and military engineering group) to begin construction of the Wall.

Organisation Todt, named after Fritz Todt - a senior Nazi engineer, who died in a plane crash in 1942 - was behind all major engineering projects in Nazi Germany and in the occupied territories, including the Siegfried Line along the Franco-German border. It was known to rely on forced labour, but - with the extreme significance of the Atlantic Wall project in Fuhrer's eyes - this time it was decided to hire 600,000 French workers from the areas controlled by the Vichy government (as well as some qualified builders from the occupied countries) for the construction.

With characteristic German precision, the whole Atlantic coastline of France was divided into 12 engineering sectors, and plans were drawn for different types of bunkers and batteries: from Regelbauten - a standard-type bunker, with all specifications to be found in the Organisation's engineering catalogues - to SonderKonstruction, a non-standard emplacement to be adjusted to a specific location. The latter were to take precedence in Northern France later, when the Nazi military campaign was failing on the Eastern and other fronts, and Hitler introduced a new propaganda term Vergeltungswaffen, or 'retaliation weapons'.

Products of Peenemunde

The two principal retaliation weapons of the Third Reich were V1 and V2. They were both designed in a secret research centre in Peenemunde, a small German village on the Baltic coast, under the supervision of Wernher von Braun, then a major in the SS, and were both operational by mid-1944.

V1, or the flying bomb, was a kind of pilotless plane. A winged subsonic missile, it used a pulse-jet engine, which operated on petrol and developed 350kg of thrust. Over 9,000 V1s, or 'doodlebugs' as the British called them, were launched on London alone, mainly from France, from specially designed and later standardised bunkers-cum-launch sites.

V2 was the most spectacular rocket developed in Peenemunde. It used the latest German achievements in the fields of propulsion, remote guidance and supersonic aerodynamics. Most modern missiles and rocket launchers are V2's direct descendants.

The first V2 rocket (formerly known as A4) was launched onto London on 7 September 1944, by which point von Braun, who had personally picked prisoners from Buchenwald concentration camp for its construction, was already thinking of space travel - the fact that prompted his famous remark : 'The [V2] rocket worked perfectly, except for landing on the wrong planet.' London was hit by 517 V2s, and several hundred more landed in surrounding counties.

It recently transpired that, on Hitler's orders, the Nazis were testing some of the Peenemunde-made V2s on German towns and cities, mostly in Pomerania, killing thousands of their own citizens.

The third retaliation weapon, the so-called London Gun, or V3, was developed in Peenemunde in spring 1943. The giant multi-charge cannon had a revolutionary new design, the main feature of which was an extremely long barrel, and its successful operation demanded special gigantic bunkers. The bunkers were duly constructed by Organisation Todt, but all the much-hyped 'superguns' were bombed out of existence by the Allies before they could fire a single shot.

Naturally, the new retaliation weapons required SonderKonstruction - bespoke tailor-made bunkers and launch sites. Those were substantial engineering structures, and some of them, including the Wall's two largest emplacements, Battery Lindemann and Battery Todt, can still be found and explored in the Pas de Calais region of Northern France.

I invite you to visit three of them.

The Eperlecques Bunker

In April, the Eperlecques Forest 10km north-east of Saint-Omer is full of the sounds of spring: the gentle rustling of young leaves on birch trees, a cheerful chorus of birds.This peaceful sylvan harmony is suddenly disrupted by a series of gun shots. Benoit Deval, my French host, explains that it's just local farmers shooting in the air to scare birds off their fields.

To me, however, the loud bangs sound like echoes of World War II. No wonder: hidden in the forest is one of the most sinister military structures I have ever set my eyes upon: the enormous Eperlecques Bunker.

Initially designed to launch V2s (32 launches per day) at London, it was built here in 1943-44 by a branch of Organisation Todt under the command of General Domberger. In August 1943, the Allies dropped hundreds of Tallboy bombs onto the site, but, thanks to the bunker's robust engineering, the damage to the giant structure was minimal: its southern part remained unscathed, and the foundations of the northern wing were affected only slightly.

Nevertheless, the Germans decided to move the V2 assembly facility to another site (5 km south of Saint-Omer), known today as La Coupole, with the Eperlecques Bunker switching over to mobile V2 launch pads and gradually being converted into a liquid oxygen plant, producing 320 tonnes of the rocket fuel a month - enough for 220 V2 launches.

The oxygen was liquefied in special underground compressors at -183°C. And although not a single V2 was launched from this site, the fuel factory carried on until it was liberated by the Canadians on 6 September 1944.

Today, the site, transformed into an open-air museum, is resplendent with disturbing war-time noises: howling air-raid sirens, exploding bombs, screaming people - the real echoes of WWII, played from multiple loudspeakers.

La Coupole

'La Coupole' means 'The Dome' in French. True, this imposing concrete structure is shaped like a huge dome, calling up associations with indoor stadiums, circuses and planetariums. And nowadays it does house Europe's first 3D planetarium, featuring an impressive 3D presentation on the history of space exploration. The planetarium occupies a relatively small part of the former V2 launch site and depot, with its dome-shaped roof (71 metres in diameter) and its 5.5-metre-thick walls.

In 1942-43, it was a real underground city, and some of Germany's top construction firms were sub-contracted by Organisation Todt to build it. 1300 workers (German, French, Belgian) and 500 specially selected Soviet prisoners of war with engineering backgrounds toiled there night and day, or, as we now say, 24/7.

On their arrival at the site, the V2 missiles, made at the Mittelwerk underground factory in central Germany, were meant to be transported to their launch or storage places via a specially constructed railway tunnel, lined at the sides with offices and fuel storage tanks. There was also a 26-tonne electricity generating plant supplying power for the whole massive complex.

Luckily, the launches never took place. Between March and July 1944, the site became the target of 16 air raids during which 3193 tonnes of bombs were dropped on it. The Allies' raids culminated in the attacks by the RAF Bomber Command's elite 617 Squadron, with its Tallboy bombs. Invented by British aeronautical engineer Barnes Walllis, these 12,000 lb (5,400kg) 'seismic' bombs created a small earthquake, which caused the quarry face beneath the dome to collapse. The Germans then abandoned La Coupole, but it was not the last time that explosions shook the air above the site.

Winston Churchill believed that La Coupole, even in its semi-demolished state, presented a potential threat to the UK, if it got into the hands of an 'enemy power' (read the Soviet Union). In May 1945, he ordered the Royal Engineers to demolish access to the site with explosives.

After that, all went quiet at La Coupole until 1997, when the museum was opened there. Despite multiple bombings and demolitions, the structure still looks relatively undamaged, as if it was built yesterday. It towers above the pastoral landscape of Northern France - as a sinister reminder of the dark power of engineering, if controlled by the forces of evil.

The Mimoyecques Fortress

The V3 supergun was Hitler's very last resort, yet despite its enormous dimensions, the London gun proved but a proverbial straw unable to stop the Fuhrer from drowning.

The weapon, which was initially tested in a forest near Magdeburg, used multiple propellant charges along the length of a very long barrel, timed to fire as the shell passed by in order to boost its velocity. It required super-large and super-deep bunkers.

Organisation Todt sub-contracted the construction work to a German company from Essen specialising in underground structures. The Mimoyecques site near Calais was supposed to comprise two identical bunkers, one kilometre apart, connected by two 30-metre-deep railway tunnels, which would also serve a network of underground galleries, built to allow the shells to be loaded into the breech locks. The active part of the bunker consisted of ten 127-metre chambers inclined at an angle of 50°, with a cluster of five guns in each so rounds could be fired in quick succession. The floor was in the shape of a staircase to permit reloading of the side chambers with powder. The barrel exits were protected by a 5m-thick concrete slab, with 20cm steel plates on top.

The Mimoyecques Fortress was 13km from the shore and hence could not be easily spotted from the coast, yet for the V3 shells, with a minimum range of 150km, London was still within easy reach.

Thankfully, the British aerial surveillance spotted some 'abnormal' activity on the site in September 1943. The first air raids in November 1943 did little damage to the emerging structure, but the subsequent, more intense, ones, culminating in the massive Tallboy bombardment on 6 July 1944, completed the job, with surprisingly few human casualties (two Germans and nine foreign workers).

It was one of these bombing missions that led to the death of B-24 pilot Lieutenant Joseph Kennedy Jr - the elder brother of the future President of the United States - when his aircraft exploded shortly after take-off from its base in Suffolk.

The gruesome bunker now stands abandoned, apart from a large colony of bats (11 species, four of which are rare). The Mimoyecques Fortress museum flyer explains that the bats were attracted to the site by three factors: stable temperature, moisture, and - wait for it - peace!

Could there be a more symbolic and more optimistic ending to our short tour of the Atlantic Wall sites?

Further information

Recent articles

Info Message

Our sites use cookies to support some functionality, and to collect anonymous user data.

Learn more about IET cookies and how to control them