Were you generous with the sun screen this summer? In Germany, vacationers may have applied it more diligently. Down on the beach, we’re all used to the warning flags that tell us when it’s safe to swim. But there’s a bigger risk that’s often underestimated: melanoma caused by sun exposure. The higher the ultraviolet index, the more dangerous the sun becomes for your skin. Germany’s Cancer Aid association decided to alert summer visitors at the most critical moments. With the agency Heimat, they created a flag whose photosensitive ink shows the sun with a black halo when the UV – and the danger – is at its highest. After successful tests in Germany it may crop up in resorts worldwide in time for next summer.