Best Visual Illusion Contest Of The Year

Here is a novel illusion that is as striking as it is simple. The two images of the Leaning Tower of Pisa are identical, yet one has the impression that the tower on the right leans more, as if photographed from a different angle. The reason for this is because the visual system treats the two images as if part of a single scene.

This illusion was the winner of the 2007 Best Visual Illusion of the Year Contest.

(via Ursi's Blog)