One of the top scuba diving areas in the United States, Biscayne National Park covers 181,500 acres (73,450 hectares), 95 percent of which lies underwater. In fact, divers and snorkelers from all over the world come to explore its extensive reef system. Above water, you can explore the park’s small mainland mangrove shoreline and Keys by boat. Biscayne National Park consists of 44 islands, but only a few of them are open to visitors. Long Elliot Key has picnicking, camping, and hiking among mangrove forests; tiny Adams Key has picnicking and equally tiny Boca Chita Key, once an exclusive haven for yachters, has the country’s second-largest lighthouse, picnicking, and camping. As the Biscayne National Park is mostly underwater, the best way to truly experience it is with snorkel or scuba gear. For beneath its surface, an underwater world explodes with multicolored life, from vibrant angelfish and parrotfish to swaying sea fans and multi-shaded labyrinths of coral.