You could call it payback time: All of those ultraviolet rays that we soaked up when we were younger finally taking their toll.

As we grow older, we often associate the wrinkles and spots that appear on our skin with other (seemingly inevitable) debilities, such as stiffening joints, sagging bodies, weakening teeth and the like. But those spots can be a sign of something more worrying than the approach of old age -- skin cancer.

Skin cancer is one of the most serious effects that UV radiation can have on the human body.