David Marshall had been among the 600,000 Americans involved in the Battle of the Bulge, the gritty faceoff against a determined Nazi onslaught that showered Belgium's snow-clogged forests with shrapnel and blood.

"You had to know what the situation was like -- the snow, the cold, the tree bursts [when artillery fire hit tree tops]," he said, describing the conditions he and others had endured during those six weeks of combat, which ended in late January 1945. "How I got through that way, I don't know. I was lucky."

But as that iconic battle was ending with a decisive Allied victory, the Manhattan draftee learned that another formidable task lay ahead.

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Marshall, a mortar crew member with the 84th Infantry Company, 3rd Battalion, 334th Infantry Regiment, 84th Infantry Division, was being ordered across the Belgian border and into the German heartland.

The struggle in Germany would be the Nazi empire's desperate last stand, one aided by the protection of two natural barriers -- the Roer and the Rhine rivers -- and by remnants of a series of concrete bunkers and tank traps known as the Siegfried Line.

Marshall, 90, a retired chemical engineer who moved to Baldwin Harbor in 1959, remembers the tingly anxiety he experienced as the Allied forces prepared to cross a contested Roer River, one whose bridges had been destroyed.

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Normally fairly narrow and shallow, flooding and Germany's intentional opening of a dam upriver had left the Roer more than 1,000 feet wide in most areas, and deep enough to swallow trucks whole. That funneled the American troops to a point in the river where the Germans awaited.

It took three weeks of planning and training to devise a crossing, using boats and temporary bridges. Throughout that time, Nazi guns would fire at the Americans from across the river.

"The Germans fought for the Roer River, between Aachen and Cologne, as if it were the Meuse, the Marne and the Somme of the last war [World War I] all rolled into one," Time Magazine wrote in its Dec. 11, 1944, edition.

Marshall remembers it that way also.

He recalls holding his breath as he crossed a hastily constructed pontoon bridge, knowing that German guns might open up on him at any time. Once safely on the other side, he was greeted with a nightmarish landscape. Twisted timbers of bombed-out houses sprawled onto village streets. Shattered trees provided no shade for the corpses of men and horses who lay along the way.

"From there, we had fierce battles until we got to the Rhine," Marshall said.

"We ran through towns very quickly but careful not to get sniped at or booby-trapped," he said. "You had to be careful about that."

He also described coming upon Siegfried Line bunkers still occupied by German machine gun crews. American soldiers had to find ways to reach them on foot if their guns were to be silenced. Crawling in the mud to avoid machine-gun fire left GIs cold and waterlogged.

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"The ground for over 100 yards in front is flat, so the field of fire that the gunners had was just perfect, absolutely perfect," he said. "So losses were high. It was just impossible not to have losses like that. It's hard to really put into words how difficult."

But he said it became clear that the will of the German army had been broken.

German soldiers -- many of them hastily recruited farmers, shopkeepers and bureaucrats -- began surrendering in increasing numbers.

"At that point, the war went pretty fast for us," he said. "We couldn't catch the Germans, they were going backwards so fast. And we were going forward."

He said a sense of optimism gained hold.

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"After we left Belgium, and had squashed the bulge, we knew the tide had turned," he said. "They had spent a lot of energy, a lot of equipment, a lot of men were lost."

"They were putting up a fight on their home ground, they had to, but we moved constantly forward," he said. "We knew, just stay alive and the war will be over soon. Stay alive."