London, England June 1, 1944

In June 1942 members of the French Resis­tance pro­vided British intel­li­gence with a copy of the top-secret blue­print of portions of Adolf Hitler’s Atlan­tic Wall—part of the defenses against the anti­ci­pated Allied in­va­sion of West­ern Europe. The map had been spirited from the office of the German public works bureau that was building the coastal defenses, and it revealed the strong and the weak points along the entire North­western French coast of Normandy, from Cherbourg in the west almost to Le Havre in the east.

The French Resistance continued to pass the Allies detailed infor­ma­tion about the Nor­man­dy in­va­sion area (gun emplace­ments and caliber, real and fake mine­fields, gaps in German flak defenses, etc.) right up to D-Day—infor­ma­tion pro­vided in part by some of the thou­sands of French laborers, foreigners who had been pressed into forced labor, and Ital­ian POWs Field Marshal Erwin Rommel (he of Afrika Korps fame) was using to build stronger coastal defenses, plant millions of land­mines (6 million in Northern France alone) and a variety of shallow-sea naval mines, flood large areas behind the flat beaches to drown Allied para­troopers, and drive long anti-airborne stakes called “Rommel’s aspar­agus” into open fields to thwart the safe landing of Allied troop gliders.

In advance of Oper­a­tion Over­lord, the code­name for the June 1944 Nor­mandy landings, Allied air­craft began pounding syn­the­tic oil plants in Germany, which reduced the Luft­waffe’s fuel supply by nearly 70 per­cent between April and this date, June 1, 1944. Allied intel­li­gence esti­mated that the enemy could lay hands on two million freight cars to move troops and supplies to the in­va­sion front. So to pre­vent the Germans from deploying, rein­forcing, and re­supplying their beach­head defenders, Allied air­craft hea­vily bombed and cra­tered French and Bel­gian high­ways, tunnels, canals, river crossings, and rail­road yards, usually in day­light. In Oper­a­tion Chat­ta­nooga Choo-Choo (May 20–28, 1944) Anglo-Amer­i­can fighter bombers strafed and destroyed French, Bel­gian, and German trains virtually with im­punity. German air bases and coastal bat­teries were bombed up and down the English Chan­nel. This forced some guns, for example the six 155mm artil­lery pieces at Pointe du Hoc that directly threatened the Allied amphib­ious armada and the two inva­sion beaches in the Amer­i­can sector, to be covertly moved inland, much to the sur­prise of U.S. Army Rangers who on D‑Day scaled the treach­erous cliffs at Omaha Beach. Between April 1 and June 6 the Allies flew 200,000 bombing sorties over North­ern France, aver­aging one ton of bombs dropped for every sortie. Nearly 2,000 air­craft were lost in these sorties.

Heavy too were the civil­ian casual­ties caused by these air raids, as well as from sabo­tage by Resis­tance fighters on the ground, partic­u­larly by Résis­tance Fer, the organ­i­za­tion of French rail­way­men: over 12,000 peo­ple lost their lives. (The Germans were quick with repri­sals, exe­cuting sev­eral hun­dred chemi­nots, as the French rail­way­men were known, and deporting another 3,000 to German camps.) But 80 classi­fi­cation/­mar­shaling yards and 1,500 loco­mo­tives were put out of com­mis­sion, along with miles of rail­road tracks (950 cuts), water pumps in the rail­way yards, major river bridges (24 just over the Seine between Paris and Rouen in Normandy), tunnels, tele­phone and tele­graph lines, heavy lifting cranes, 36 air­fields, 45 gun bat­teries, and 41 radar instal­la­tions that the enemy would desperately need to throw back the invaders.

When the first in­va­sion ships set sail from England on June 4, 1944, and troops finally set foot on Fes­tung Europa, For­tress Europe, two days later, the Allies had neu­tra­lized the Luft­waffe over France (the Germans had less than 160 ser­vice­able air­craft), degraded the enemy’s ability to move on land, and breached the “impreg­nable” Atlantic Wall in a matter of hours to rapidly forge their beachheads for the inevitable liberation of Western Europe.

German Atlantic Wall Defenses on the Eve of Operation Overlord

Atlantic Wall, 1942–1944

Above: Map of the 1,668-mile-long Atlantic Wall shown in green. Stationed behind the wall were 46 German oper­a­tional divi­sions with another 7 divi­sions in the pro­cess of being formed. The wall, which included an esti­mated 15,000 rein­forced-concrete struc­tures, hugged the coast­line from Norway to Spain in varying degrees and was most elab­o­rate facing the English Chan­nel, particularly in the Pas-de-Calais (French name of the Dover Strait), which was in sight of the English coast. Touted by Nazi Propa­ganda Minis­ter Joseph Goeb­bels to be impen­e­tra­ble, the wall con­sisted of an exten­sive system of coastal forti­fi­ca­tions built between 1942 and 1944 as a defense against an anti­ci­pated Allied inva­sion of the con­ti­nent. In France the wall com­prised a string of rein­forced con­crete case­mates housing heavy-caliber guns such as three 406mm naval guns at Battery Linde­mann between Calais and Cap Blanc-Nez opposite Dover, bunkers housing smaller artil­lery (100–210mm guns), and pill­boxes along the beaches or some­times slightly inland, occa­sional station­ary flame­throwers and search­lights, as well as barbed-wire entangle­ments, mines, and steel or con­crete anti­tank obstacles (e.g., Czech hedge­hogs and pyramid-shaped tetra­hedrons) planted on the beaches or in waters just off­shore. Admittedly a major engi­neering feat for its time, the Atlantic Wall, in the opinion of the ines­ti­ma­ble Stephen Ambrose, author of D-Day June 6, 1944: The Climactic Battle of World War II, “must . . . regarded as one of the greatest blunders in mili­tary his­tory”; to wit, at Utah Beach the wall held up the invading U.S. 4th Divi­sion for less than one hour. At Omaha the wall delayed the 29th and 1st divi­sions for less than a day. At Gold, Juno, and Sword it held up the British and Cana­dian in­vaders for about an hour. “Once it had been penetrated, . . . [the Atlantic Wall] was useless,” Ambrose said.

German Atlantic Wall defenses: Rommel and officers inspecting Atlantic Wall, France, April 18, 1944German Atlantic Wall defenses: Planting high wooden poles on French beaches, 1944

Left: In late November 1943 Field Marshal Erwin Rommel took com­mand of the ad hoc German Army Group B in occu­pied France, reporting directly to Hitler. (Only in mid-January 1944 did Hitler place the Seventh and Fif­teenth Armies under Rommel, thus making Heeres­gruppe B an oper­a­tional reality under Ober­befehls­haber West Field Marshal Gert von Rund­stedt.) Rommel, in his role as Inspec­tor-Gene­ral for Northerrn Europe, was also respon­si­ble for Atlantic Wall defenses on the French coast facing England, as well as those from Bel­gium north to Den­mark. Above almost every­one else in the German High Com­mand, Rommel was a genius at waging suc­cess­ful war even against a more numer­ous and better-equipped foe. To do this Rommel employed his own men, con­scripted civil­ians, brought in slave laborers, and made use of more than a quarter million foreign workers, working hun­dreds of thou­sands of men to exhaus­tion, to make the French coast as imper­vious as possi­ble to inva­sion. “We’ll have only one chance to stop the enemy, and that’s while he’s in the water . . . struggling to get ashore,” he preached on hectic inspec­tion tours. In this photo, likely taken on April 18, 1944, when he was accom­panied by four war corre­spon­dents, Rommel, his offi­cers, and comman­ders of the posi­tions under­going inspec­tion can be seen in­specting an instal­la­tion of 15- to 20‑ft wooden obstruc­tion beams (Hemm­balken), three to six rows deep, on a beach near Calais meant to disrupt an amphib­ious oper­a­tion, whether at high or low tide. Some beams were topped with lethal saw­tooth devices and artil­lery shells or Teller (German for “plate”) mines to rip open or detonate when Allied landing craft passed over them. The Allies modi­fied their origi­nal plans to land troops at high tide, closer to the shore, in favor of landing at a rising tide when the obstruc­tions and mines could be seen and avoided. The disad­van­tage with the revised plan was that it increased the length of beach to be crossed.

Right: In 1943 German troops had begun using hy­drau­lic pres­sure hoses to assist in planting high wooden poles (Hoch­pfaehlen) in beach sand as obstacles to landing craft. Pres­sure hoses knocked instal­la­tion time from 45 minutes to three or four minutes compared to using clumsy pile-drivers. In Febru­ary 1944, on a tour of Chan­nel beaches in Pas-de-Calais (since 2016 part of Hauts-de-France) oppo­site England, Rommel ordered the tech­nique used to place wooden beams, hedge­hogs made out of steel girders, and other anti­landing ob­struc­tions along Normandy’s beaches. Out of over four million mines laid on Chan­nel beaches between Calais and Cher­bourg on the Coten­tin Penin­sula, nearly 11,000 were installed on the coast­line where the Allies would land. Despite the measures taken in forti­fying the northern coast of France, Rommel sensed they would not be enough to throw the invaders back into the sea. What’s more, the kind of man­power he needed to do justice to the job so far was simply not there—casualties in other theaters of war.

German Atlantic Wall defenses: German sketch for log and wire defenses against airborne forces, 1944German Atlantic Wall defenses: "Rommel’s asparagus" in French field, 1944

Left: Rommel sent his subordinate com­manders sketches like the one depicted here for laying out wooden log and wire defenses against airborne assaults. Barbed wire and trip­wires were to be strung between the poles. The com­plete system of wooden poles and interconnecting wires was called Luftlandehindernis.

Right: “Rommel’s asparagus” (Rommelspargel) refers specif­ically to wooden poles used against aerial in­va­sion. Wooden tree trunks and logs set in French fields and mea­dows in 1944 were intended to cause damage to mili­tary gliders (e.g., by tearing off their wings) and to kill or injure glider infan­try in an uncon­trolled landing. Though more than a million of these fiendish wooden spears were erected, their effect on the invasion of Normandy was inconsequential.

Rare Color Footage: From D-Day to Liberation of Paris, 1944