Since ancient times, human beings have known the sun can be dangerous. Too much exposure to its rays can burn and prematurely age the skin. In fact, the concept of sunscreen may be a non-human invention, as various types of animals coat themselves in protective layers of mud to stave off the at-times brutal effects of heat and sunshine. Fast forward to the modern era -- sunscreen is a huge industry, and people across the planet use it on a daily basis. The science seems sound. Unlike some skin care products, sunscreen actually works... however, it appears sunscreen may also have a dark side. Tune in to learn more.