H-hour was set for 6:30a.m.  The hour was growing near.  The plans had finally begun to spin into motion.  The night before the paratroopers, pathfinders, and glider trains had been dropped deep into German territory.  Although many problems occured such as misdrops and confusion due to the drops they had begun the attach and set the stage for the seaborne invasion.  At 5:30 the first wave of troops were well on there way.  This the great seaborne invasion that the free world had struggled so hard for, now rested on the shoulders of about 3,000 soldiers in the first wave.  They were leading the attack and they were the men of the 1st, 4th, and 29th divisions.  Omaha beach had been divided into zones, the other beaches were also divided.  The 1st division would land on Easy Red, Fox Green and Fox Red.  The 29th division would land on Charlie, Dog Green, Dog Red, Dog White, and Easy Green
This is an example of one of the many machine gun nests, littering the great wall.
Minute by minute planning had been set out for the invasions.  One example can be Omaha.  H-hour minus 5(5:25) 32 amphibious tanks were two swim onto Dog White and Dog Green and provide cover.  At H-hour 8 C.C.T.'s would bring more tanks for cover on the Easy Green and Dog Red.  At H-hour plus 1 assault troops would swarm all sectors.  6:33 a.m. underwater demolition engineers were to clear 16    50 yard paths through mines and obstacles, they had just 27 minutes to do this.  Starting a 7:00 a.m. at 6 minute intervals 5 assault waves, the main body of troops, would begin to land and attack the beaches.
The hardships of the troops are often not documented until they hit the beaches, but they ran into many on their approach.  They encountered massive bouts of seasickness.  Also because of the amount of equipment they carried when a boat would sink or get hit, the troops would not be able to swim for long.  They would cry in vain for the passing L.C.'s to stop and help them but they were not allowed to avert from their current path.  This led to the agonizing deaths of many before even seeing land. 

The great wall proved to be much more defended than just obstacles, mines, and concrete.  The beaches were stocked with countless men and armorments.  One example is Omaha.  Omaha beach consisted of 8 concrete bunkers with guns of 75mm or greater, 35 pillboxes with artillery pieces and/or automatic weapons, 4 batteries of artillery, 18 antitank guns,  6 mortar pits, 35 rocket launching sites- each with 4 38mm rocket tubes, no less then 85 machine gun nests, and countelss men with small arms.
At around 5:30 the air attack on the bluffs began, providing cover for the men to come.  6:30, H-hour, L.C's began to hit the beaches.  The problem was that the machine gunners and artillery personel would hit the craft the minute the front opened, eliminating most of the men right away.  Dog Green and Fox Green of Omaha were two of the fiercest defended zones.  nearly entire units were wiped out at these zones.  Company C. of the 75th Rangers started with 75 men and by the end of the day were down to 12.  Experiences differed on different beaches.  Some men refered to Utah as a routine experience.  Throughout the assault naval ships continued to bombard the bluffs.   Only one major gunship was lost and that was the U.S.S. Corry.  Men of the 2nd Ranger division were dealing with one of the toughest tasks of the day.  That was to scale a section of 9 story cliffs.   They had support from men on fire ladders in amphibious vehicles off shore.  As they climbed the Germans would lean over the edge and pepper them with machine gun fire and cut their ropes.  After much stuggle they made it to the top.
A shell explodes on one of the beaches
non-linked pictures courtesy of The Longest Day by Cornelius Ryan
Patrick McGinnis 2/3/00 www.oocities.org/paddyjoe_m/day.html