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Marianas Trench Marine National MonumentThe United States' nearly 1,800 marine protected areas contain some of the country's most spectacular reefs, underwater archaeological sites, and most valuable commercial fisheries and tourist diving sites.Ranging in size from less than one square mile (2.6 square kilometers) to over 139,797 square miles (362,073 square kilometers), the sites are located from the Arctic to the South Pacific, from Maine to the Caribbean, and as far west as the Philippine Sea.The Marianas Trench Marine National Monument, established in 2009, and covering 95,216 square miles (246,608 square kilometers) of submerged lands, is one of the largest marine protected areas in the world. Within and adjacent to the Mariana Archipelago, the monument includes three areas of undersea mud volcanoes, more than 1,000 miles (1,609 kilometers) of the Mariana Trench, and the waters and submerged lands around some of the northern Mariana Islands.Explorers and scientists are discovering strange and fantastic new species and habitats as they bridge this final frontier on Earth into the deep-sea. Advances in technology and engineering are opening up parts of the world once only dreamed of, while spotlighting the importance of conserving them as found, for future generations.

Photograph by Paul Chesley