It turns out that even big-budget blockbusters aren't exempt from the occasional slip-up. Someone call the costuming department, because these wardrobe fails haven't gone unnoticed...
The Ten Commandments (1956)
When Nefertiti is seen wearing a teal silk dress in The Ten Commandments, costume designers made an accidental no-no. The movie was supposed to have taken place between the 16th and 13th centuries, during which the only way to dye silk was with natural tints. A blue dress wouldn't have existed at that time.