Most people have had at least one vacation ruined by sunburn. Usually, they then smarten up and remember that heading outside means putting on sunblock. Children are frequent victims of sunburn, their time in the sun flying by as sandcastles get bigger and bigger. We grown-ups can be caught unaware, too. Whether skiing, backpacking, or just sprawled on the chilly deck of a cruise ship, we just don’t notice until it’s too late how the dazzling sunlight has baked our pale arms, legs, and face into a glowing lobster red.