The film is a highly fictionalized version of actual events during the last months of World War II when the 9th Armored Division approached Remagen and captured the intact Ludendorff Bridge. Instead of the real week-long battle and several artillery duels fought between the Americans and German defenders, the film focuses on the heroism and human cost in gaining a bridgehead across the Rhine before the Allies' final advance into Germany.
The film opens with the U.S. Army failing to capture the still-intact Oberkassel railway bridge. Lieutenant Hartman (George Segal) is an experienced combat team leader who is becoming weary of the war in Europe. After he is promoted to company commander following the reckless death of the previous officer, he is given orders to advance to the Rhine River at Remagen where he is promised a rest for his men. At the same time, Major Paul Kreuger (Robert Vaughn), an honorable Wehrmacht officer, is given the job of destroying the bridge there by his friend and superior, Colonel General von Brock (Peter van Eyck), who has been given a written order to do it immediately. But the staff officer appeals to Kreuger's sense of honour, giving him a verbal command to defend the bridge for as long as possible to allow the 15th Army trapped on the west bank of the river to escape.
After capturing the undefended town of Meckenheim, four miles from Remagen, Hartman is ordered by his battalion commander, Major Barnes (Bradford Dillman), to continue the advance until encountering resistance. Hartman is disgusted because Barnes is using the men's lives to further his own military career. Kreuger, meanwhile, has been touring the defences above the town of Remagen. He assures the handful of troops, which are just old veterans and boys, that he has a personal guarantee from the general that tank reserves are on the way. But when Hartman's troops attack the town, Kreuger is shown the reality when he calls for the promised tanks and is told they have been sent "elsewhere".
On finding the bridge intact, General Shinner (E. G. Marshall) orders Major Barnes to secure its capture, saying: "It's a crap shoot, Major. We're risking one hundred men, but you may save ten thousand". With only momentary hesitation, Barnes agrees to send in Hartman's company, and orders the troops to gain a foothold across the Rhine River, thus avoiding a costly assault-crossing elsewhere. Sergeant Angelo (Ben Gazzara), one of Hartman's squad leaders and friends, highlights the mood of the war-weary men by striking Barnes after being ordered onto the bridge.
On the other side, as the American soldiers rush the bridge, Kreuger, along with explosives engineer Captain Baumann (Joachim Hansen) and Captain Schmidt (Hans Christian Blech) from Remagen Bridge Security Command, tries to blow up the bridge, but the explosives they use prove to be not the high-yield military grade charges needed for the job, but weaker industrial explosives, which fail to destroy the superstructure. Hartman's troops dig in to consolidate their hold on the intact bridge.
Kreuger, who still believes in victory, shoots two soldiers as they try to desert. He then realises that the futility of the situation has turned him on his own troops and the defensive position has becomes untenable. In desperation, Kreuger returns to HQ to make a personal appeal to the general for more reinforcements, but on arrival he finds that the building has been taken over by the SS and Von Brock has been arrested for being "defeatist". Kreuger is then questioned about the delay before blowing up the bridge. Unable to present a written order, he is not able to justify his actions and is arrested.
Back at Remagen, Hartman leads a raid against a machine gun nest installed by Kreuger on board a barge moored to the bridge, but while taking its crew out, Angelo is hit and falls into the river. Despondent, Hartman marches on foot towards the bridge defenders' post at the same time as a squad of M24 Chaffee light tanks cross the bridge. The remaining German soldiers surrender to the Americans, and in the aftermath Hartman discovers that Angelo has survived after all. The next day, Kreuger is led out for execution by SS firing squad. With the sounds of many planes overhead, Kreuger asks: "Ours or theirs?". The SS officer attending him replies, "Enemy planes, sir!". "But who is the enemy?" muses Kreuger before he is shot. (In reality, Hitler ordered five men responsible for the failed defense shot: one was convicted in absentia, four others killed).
The film concludes with scenes on the bridge, and a screen crawl informing the viewer that the actual structure collapsed into the Rhine 10 days after its capture.George Segal as Lieutenant Phil Hartman (based on Lt. Karl Timmermann)
Robert Vaughn as Major Paul Kreuger (based on Major Hans Scheller)
Ben Gazzara as Sergeant Angelo (a composite of Sergeants Alexander Drabik and Joseph DeLisio)
Bradford Dillman as Major Barnes (based loosely on Major Murray L. Deevers)
E. G. Marshall as General Shinner (based on Brigadier General William Hoge)
Peter van Eyck as Generaloberst von Brock (based loosely on Generalleutnant Walter Botsch)
Hans Christian Blech as Hauptmann Karl Schmidt (based on Hauptmann Willi Bratge)
Heinz Reincke as Councillor Holzgang, the Mayor in charge of civil defence
Joachim Hansen as Hauptmann Otto Baumann, engineering officer (based on Hauptmann Carl Friesenhahn)
Sonja Ziemann as Greta Holzgang
Anna Gael as French Girl
Bo Hopkins as Corporal Grebs
Robert Logan as Private Bissell
Matt Clark as Cpl. Jellicoe
Steve Sandor as Pvt. Slavek
Frank Webb as Pvt. Glover
Tom Heaton as Lt. Pattison (based on Lt. Emmett James "Jim" Burrows)
Paul Prokop as Capt. John Colt
Richard Münch as General von Sturmer
Günter Meisner as SS-Oberstgruppenführer Gerlach
West German officials would not allow the production to make the film in Germany because of shipping traffic on the River Rhine. Instead, the film company made the film in what was then Czechoslovakia.
Much of the Remagen town scenes were shot in the town of Most. The old town was being demolished and rebuilt at a new location at the time in order to make lignite lying under it accessible for mining.
The Remagen Bridge scenes were shot at Davle on the Vltava River using the old bridge. Fake towers and a fake railway tunnel were constructed for the film. The film's opening scenes – where the US Army fails to capture the Oberkassel, Bonn bridge – were shot just south of the village of Vrané nad Vltavou using the railway bridge which carries the Prague-Dobříš line over the River Vltava.
During the filming in 1968, the Soviet Army invaded Czechoslovakia to reinstall a hard-line Communist government, forcing the film cast and crew to flee to the West in taxis. In 2007, Vaughn played himself in a BBC Radio 4 dramatisation of the events surrounding the invasion.
The Bridge at Remagen was released in theatres on June 25, 1969. The ABC network broadcast the film on television in the U.S. on July 24, 1977. The film was released on DVD by MGM Home Entertainment on January 24, 2006 and January 31, 2006.