This film portrays what we’d likely classify today as a docu-drama, showing the actual attempts by British soldiers to seize and maintain the bridge at Arnhem in Holland, so that others could advance. It's evident throughout that this was an extremely detailed undertaking involving many personnel and substantial equipment, and once it started, the true devastation of war is laid bare. The filmmakers don’t shy away from the harsh realities; while not overly graphic, it effectively demonstrates how perilous the situation was, and how prepared and entrenched their German adversaries were—just as resolute in refusing to give way. Because the outcome of the battle is already known, what makes this presentation particularly relevant is the inclusion of veterans and other soldiers who participated in an event that can hardly be considered a victory - 10,000 went in, only 2,000 returned—but that's precisely why their actions were so extraordinary. The film doesn’t hesitate to present the tragedy of this operation as it might have occurred in 1944. There's a moment about halfway through at an emergency medical facility where someone inquires "Are they still operating?" and is told, “No, the roof has just collapsed.” It was certainly no easy task.

Source on TMDB