When on D-Day-June 6, 1944-Allied armies landed in Normandy on
the northwestern coast of France, possibly the one most critical event
of World War II unfolded; for upon the outcome of the invasion hung
the fate of Europe. If the invasion failed, the United States might
turn its full attention to the enemy in the Pacific-Japan-leaving

Britain alone, with most of its resources spent in mounting the
invasion. That would enable Nazi Germany to muster all its strength
against the Soviet Union. By the time American forces returned to

Europe-if indeed, they ever returned-Germany might be master of the
entire continent.

Although fewer Allied ground troops went ashore on D-Day than
on the first day of the earlier invasion of Sicily, the invasion of

Normandy was in total history\'s greatest amphibious operation,
involving on the first day 5,000 ships, the largest armada ever
assembled; 11,000 aircraft (following months of preliminary
bombardment); and approximately 154,000 British, Canadian and

American soldiers, including 23,000 arriving by parachute and glider.

The invasion also involved a long-range deception plan on a scale the
world had never before seen and the clandestine operations of tens of
thousands of Allied resistance fighters in Nazi-occupied countries of
western Europe.

American General Dwight D. Eisenhower was named supreme
commander for the allies in Europe. British General, Sir Frederick

Morgan, established a combined American-British headquarters known as

COSSAC, for Chief of Staff to the Supreme Allied Commander. COSSAC
developed a number of plans for the Allies, most notable was that of

Operation Overlord, a full scale invasion of France across the English

Channel.

Eisenhower felt that COSSAC\'s plan was a sound operation.

After reviewing the disastrous hit-and-run raid in 1942 in Dieppe,
planners decided that the strength of German defenses required not a
number of separate assaults by relatively small units but an immense
concentration of power in a single main landing. The invasion site
would have to be close to at least one major port and airbase to allow
for efficient supply lines. Possible sites included among others, the

Pas de Calais across the Strait of Dover, and the beaches of Cotentin.

It was decided by the Allies that the beaches of Cotentin would be the
landing site for Operation Overlord.

In my opinion, the primary reason that the invasion worked was
deception. Deception to mislead the Germans as to the time and place
of the invasion. To accomplish this, the British already had a plan
known as Jael, which involved whispering campaigns in diplomatic posts
around the world and various distractions to keep German eyes focused
anywhere but on the coast of northwestern France. An important point
to the deception was Ultra, code name for intelligence obtained from
intercepts of German radio traffic. This was made possible by the

British early in the war having broken the code of the standard German
radio enciphering machine, the Enigma. Through Ultra the Allied high
command knew what the Germans expected the Allies to do and thus could
plant information either to reinforce an existing false view or to
feed information through German agents, most of it false but enough of
it true-and thus sometimes involving sacrifice of Allied troops,
agents or resistance forces in occupied countries-to maintain the
credibility of the German agents.

Six days before the targeted date of June 5, troops boarded
ships, transports, aircraft all along the southern and southwestern
coasts of England. All was ready for one of history\'s most dramatic
and momentous events. One important question was left unanswered
though: what did the Germans know?

Under Operation Fortitude, a fictitious American force-the 1st

Army Group-assembled just across the Channel from the Pas de Calais.

Dummy troops, false radio traffic, dummy landing craft in the bay of
the Thames river, huge but unoccupied camps, dummy tanks-all
contributed to the deception. Although the Allied commanders could not
know it until their troops were ashore, their deception had been
remarkably successful. As time for the invasion neared, the German\'s
focus of the deception had shifted from the regions of the Balkans
and Norway to the Pas de Calais. The concentration of Allied troops
was so great, that an invasion of France seemed inevitable. Bombing
attacks, sabotage by the French Resistance and false messages from
compromised German agents all focused on the Pas de Calais with only
minimal attention to Normandy. Also, German intelligence thought that
the Allies had 90 divisions ready for the invasion (really only 39),
so that even after the invasion of Normandy, the belief could still
exist that Normandy was just a preliminary measure and the main
invasion of the Pas de Calais was still to come. None of the German
high command in France doubted that the invasion would strike the Pas
de Calais.