A couple of my favorites from the Bible:
- The Bible does not specify how many wise men came from the East to see Jesus after he was born, nor does it specify when exactly after the birth that they showed up. Three have been popularly depicted in paintings and nativity scenes as being right there in the stable after the birth (even though it says in Matthew 2 they entered "the house"), probably because it says they came bringing gold, frankincense, and myrrh (3 types of gifts). But for all we know it could have been way more than just three, and there could have been some interval between the birth and their arrival (perhaps weeks or months, or even a few years later). The depiction of the Magi being there with Jesus in the stable right after he was born could be a conflating of the shepherds coming to see him, which the Bible does say did happen right after the birth. The Bible doesn't name any of Magi (Balthazar, etc.) nor mention that they were kings of any kind, as is popularly depicted.
- The Bible does not specify that the fruit that Adam and Eve ate from was an apple, or anything in particular. Just that it was a fruit. In art, it is almost always depicted as an apple, but Genesis does not specify.