You can't help but enjoy the Great Escape, Sturges' produced a genuine piece of art, there's no doubt it is a truly great film... but I wonder how it changes our perception of reality. Most of us know the film is "based on real events" but which of the events it shows are real & which are fiction? A lot of people I know have seen the Great Escape, but very few know much about the historical reality.
The Escape took place in nice weather in the film, it actually took place in one of the coldest winters Poland had for decades & the weather hampered escapees more than anything else. Many were wearing light clothes, many came close to frostbite & were forced to sleep in obvious shelters, increasing their risks of being captured. The Great Escape wasn't unique, there were some 11 mass breakouts before it but the increase in security after these attempts made mass breakouts less likely to succeed, in fact, a German in Stalag Luft III even advised PoWs to escape in twos or threes to improve their chances. The idea that the escape caused huge problems for the Germans wasn't true either. No German troops were withdrawn from the frontline, they only used existing capacity inside the Reich, what the Escape did do because of the large-scale hunt was result in thousands of other escaping PoWs, regular prisoners & absent foreign workers being rounded up in the trawl as well. But maybe the obvious myth of the film was American PoWs escaping, US airmen had been moved to a different compound several months before the Escape & none were involved. The motorbike scene in the film is glorious & iconic but also proved such a gross misrepresentation that it was actually booed by former PoWs when they were first shown the film.
The reason for casting an American as the central character in the Great Escape? To appeal to the audience the film was being aimed at; in order to sell the film. Orwell's 1984 showed Winston Smith altering historical records in order for the Party to control the people's perceptions of the past, Hollywood does that in a far more subtle & seemingly less sinister way; it's not always for a political agenda (although that isn't uncommon), it's mainly for commercial reasons, they alter history based on what they think will sell best to the audience they're aiming at. Either way, the reality of the past is changed for huge numbers of people.
Buy it, you'll love it... but keep in mind it's not really about the reality it implies that it is.