The Leaning Tower Illusion• What we see of the world is what we know of the world. Although the two images are identical the right hand tower seems to be leaning more "... because the visual system treats the two images as if part of a single scene. Normally, if two adjacent towers rise at the same angle, their image outlines converge as they recede from view due to perspective, and this is taken into account by the visual system. So when confronted with two towers whose corresponding outlines are parallel, the visual system assumes they must be diverging as they rise from view, and this is what we see."
(from http://illusioncontest.neuralcorrelate.com/)
