Key Largo is built around one activity: the reef. John Pennekamp Coral Reef State Park and the adjacent Florida Keys National Marine Sanctuary protect the only living coral barrier reef in the continental United States, and every dive shop and tour operator in town is organised around getting you into the water. Divers aim for the deeper wrecks and reef walls; snorkellers can see elkhorn and brain coral formations in just a few feet of water. Above the waterline, kayaking through the mangrove channels of Florida Bay and spotting wildlife in the Crocodile Lake National Wildlife Refuge give good reasons to stay dry.