At dawn on D-Day the US Army's most experienced, battle-tested infantry formation, 1st Division or 'The Big Red One' launched its attack on Omaha Beach. The assault wave was launched too far out to sea and the men suffered terribly from seasickness. All the amphibious tanks sank except two, depriving the infantry of armoured support against minefields, bunkers and other defences. Moreover, the Allied aircraft tasked with destroying the fortifications had dropped their loads on open country too far inland and the offshore bombardment was hampered by poor visibility. Of the first six landing craft, two sank while the remainder ran aground on a sandbank.

The assaulting infantry were compelled to wade in shoulder-high water, many drowning or being shot as they struggled ashore. All cohesion was lost and following waves of infantry simply stumbled into the carnage on the beach, the piles of wreckage restricting movement. In these first harrowing hours of the invasion, Lieutenant-General Omar Bradley considered aborting the Omaha effort altogether. Despite these appalling difficulties, a vulnerable bridgehead some 1.5 km inland had been established by the evening of 6 June 1944.