Palmyra Atoll
It is the northernmost of the Line Islands, and one of three American islands in the archipelago, along with Jarvis Island and Kingman Reef. Palmyra Atoll is part of the Pacific Remote Islands Marine National Monument, the world's largest marine protected area. The atoll is composed of submerged sand flats along with dry land and reefs. It consists of three lagoons separated by coral reefs. The western reef terrace is one of the biggest shelf-reefs, with dimensions of . Over 150 species of coral inhabit Palmyra Atoll, double the number recorded in Hawaii.