In Ebihens, France, an interesting natural optical illusion can be seen called the Apache Head in the Rocks. A face can be seen looking to the left. Green grass growing on top of the mountain, resembling hair, further enhances the illusion.
Optical illusions like this one are a result of something known as pareidolia. This is a psychological phenomenon where something random or vague is perceived as having some significance. The most common example used to describe pareidolia is when a face, animal or some other figure can be seen in clouds or rocks. To see another example of this, you may want to revisit our previous post where the head of an elephant could be seen on the face of Mars.