What German defenses did the Allies face on D-Day?

Answer 1

Defense of Fortress EuropeThere were bunkers full of Germans loaded with machine guns.

There were also inland defenses. The German army flooded fields (to drown paratroopers, this worked very well) they also had the natural defenses of the Normandy hedgerows, these proved weaknesses in the allied tanks and perfect for ambushes.

on the beaches there were AT mines, tank spikes and holes dug into the beach (a fully equipt soldier would drown in these, the british did this in fear of a German invasion)

These defenses were so good that even the preliminary bombardment by the air forces and naval forces couldn't dislodge the defenders as planned

ANSWERSpecifically, the defence of the Normandy coast was provided by the German 7th Army and the 5th Army located around Caen. The surf line was ridden with all sorts of contraptions such as wooden poles with naval mines on top, X shaped iron hedges, "Belgian gates" (iron A frames meant to stop landing craft), AT and anti-personnel mines and barbed wire.

The overhangs were indeed defended from concrete bunkers and machine-gun nests of which many had survived the initial air and naval bombardment, especially on the American landing beaches, and further inland there were flooded marshes and artillery positions.

One particular defence was 'Rommels Asparagus', spikes designed to impale paratroops.

Answer 2

The Germans decided to defend at the shore, building elaborate fortifications and obstacles such as those at Omaha Beach. These were generally manned by lower quality units, since the fighting in Russia required a huge commitment of the available troops. A higher-quality mobile reserve was stationed inland, ready to react to an invasion, but it required the beach units to hold the line until it could move to where it was needed. There were a few weaknesses to this strategy (although any strategy for defending all of France would have had weaknesses). One is that it requires you to defend every conceivable landing area, even though the Allies would probably only land at one of them. So your resources are spread very thinly. The second weakness is that you have to be correct when you decide to commit your reserve -- you can't commit it until you know that the invasion is real and not a feint, but you can't wait too long or the enemy builds up too much strength to be repelled. The Allies used this second weakness to their advantage by engaging in a massive deception operation to make the Germans believe that the true invasion was going to be at Le Havre, more than a hundred miles from the Normandy beaches. The German leadership, including Hitler, clung to this belief for far too long before they finally committed their mobile units to the Normandy area, by which time the Allies had landed hundreds of thousands of soldiers.