As time passes, wrinkles typically appear. These skin depressions that become deeper and deeper draw more and more coarser lines on almost all the visible parts of aging individual's skin. They are indeed the most obvious and maybe disliked signs of skin aging, and thus, preventing and treating them are a major topic for dermo-cosmetic laboratories. However, the cause and occurrence mechanism of these simplistic looking lines are not yet fully understood. Wrinkling is thought to be a complex biophysical process resulting from repeated strains on a progressively, structurally and biochemistry altered aging skin with impaired mechanical properties. Focus is made on the specific histological features of the wrinkle compared to the surrounding aging skin. The numerous age-related changes in human skin that are supposed to be involved in wrinkling are briefly reviewed, and the current theories on wrinkle formation linked to these changes are also discussed.