Documentary: Nazi Mega Weapons: Atlantic Wall

The first section of the Atlantic Wall was built as an offensive weapon; across the channel from England, where the large canon could reach England, and did in fact destroy homes and kill people.  However when the war shifted to Russia, Hitler forgot the Atlantic coast for a time.  When the United States joined the war theAtlantic coast now seemed vulnerable.  In earnest Hitler began construction of a 3000 mile wall.  Many of the first large emplacements were essentially battleships on land with large canon turrets set in concrete.  However the Germans were running out of resources.  Only half of the wall was completed.  General Rommel took charge, any many more defensive measures were added, machine gun pill boxes, mines and obstacles were added.  hitler assumed the attack would occur at a hardened port, where earlier raids had taken place. However these raids taught the Allies that these areas were too heavily fortified.

On D-day the defenses were formidable, but fell in about three hours.  The Germans were spread too thin, and their ammunition was depleted after three hours.  Even so 10,000 allies lost their lives.