Is it time for another optical illusion? I think it is!
Believe it or not... that is the same image twice. No, really. I'll wait while you go to photoshop or gimp or your image software of choice. Or, you can just blink really fast - it'll trick your brain. Totally. I'm not even there to watch you, what makes you think I'm messing with you?
The explanation, as near as I can tell, is that your brain sees the image as one scene. Thus, the tower on the left is used as a point of reference for the vertical of the tower on the right. The result is that the image on the right seems to be significantly more skewed than the image on the left.
(Thanks to The Thinking Blog for the heads-up.)
(Who tried the blinking thing? It totally worked didn't it?)