Two identical pictures but one is upside down 

This is called the Thatcher effect, I think it was a picture of Margret Thatcher that they did that too.
Your brain is hard wired to see faces and as a child they can appear at any angle above you so it's the eyes and mouth that are more important.

Thanks for the excellent explanation Snowy 

I wonder what else our brains are hard wired to that we haven't discovered yet? After all it wasn't that long ago that Margret Thatcher was around, quite a recent discovery really.

I think I saw that on QI. It reminds me of another cool brain thing:

Another one.