The US Army's surprise capture of the Ludendorff Bridge over the Rhine River at Remagen, Germany, broke open Germany's defenses in the west. The Rhine is no ordinary river. About 766 miles in length, with an average width of about 1,300 feet, the generally north-flowing waterway also is exceptionally swift and deep.

The crossing of the Rhine River in early 1945 was one of the final and most significant strategic hurdles for the Allied forces in World War II. The Rhine was Germany's last major natural line of defense. A pivotal moment occurred on March 7, 1945, when U.S. troops unexpectedly captured the Ludendorff Bridge at Remagen intact. German defenders had failed to blow up the bridge, allowing the Allies to establish their first bridgehead on the eastern bank. Later that month, Operation Plunder (a massive amphibious crossing) and Operation Varsity (the largest single-day airborne operation in history) saw British, Canadian, and American forces swarm across the northern Rhine. These crossings broke the back of German resistance in the west, allowing the Allies to encircle the Ruhr industrial heartland and race toward the Elbe River. The campaign was characterized by intense engineering feats, as thousands of "Bailey bridges" and pontoon structures were constructed under fire to move tanks and heavy equipment across the water, effectively signaling the imminent collapse of the Nazi regime and the end of the war in Europe.