9. Not So Great Britain (Captain America: The First Avenger)
Caps origin story is still one of the best MCU movies, with Steve Rogers involvement in WWII a necessary part of the wider Marvel back-story. Starting out in 1942 when a young and scrawny Steve Rogers is deemed unfit for the US Army, we literally see his transformation into the worlds first super-soldier. With a good chunk of the picture set in Great Britain, it was filmed on location across England, though a few more patriotic Brits on set might have meant a number of mistakes could have been pointed out before they made it to screen. After the action moves across the pond to London, the Union Jack flag can be seen hanging upside down (the broad white diagonal band should be above the red one on the side nearest the flag pole) and this would have been noticed by your everyday Englishman during war time. There is also a reference made to MI6 (which didnt exist under that name until after the war) and a FV432 armoured personnel carrier can be seen outside Hydras base, even though these particular vehicles were not used by the British Army until the 1960s.