Indiana Jones and the Last Crusade (1989)
Although the Nazi costumes in Indiana Jones and the Last Crusade might seem factually accurate, there was a major flaw with the depction of their uniforms. The Nazis can be seen with a number of medals on their uniforms, but medals like this were not added to uniforms until after the end of World War II. Since the film was set in 1938, World War II had hardly begun yet.
Glory (1989)
Matthew Broderick, Cary Elwes, and Morgan Freeman starred in Glory, an American Civil War film about the 54th Massachusetts Volunteer Infantry. Here, one of the soldiers in the film can be seen wearing none other than a digital watch. Digital watches weren't invented until 61 years later in 1923.