The luster of a beautiful beach—vivid blue water, cloudless skies, warm sand—belies the innate perils of the shore. Beaches are subject to the unpredictable, wild nature of our environment. They harbor hazardous plants and animals. They get polluted. They sustain dangerous wave conditions. We don't want to scare you, but we do want you to be safe on your vacation. Here are 10 common dangers of which you should be aware before your next trip to the seashore.