File:The Bright Blue Reefs of Grande Terre, New Caledonia (MODIS 2021-08-05).jpg

English: The exceptional natural beauty of the reefs of New Caledonia shines brightly in this true-color image acquired on August 4, 2021, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite.

The bright blue reefs that shimmer around Grande Terre Island are part of one of the most extensive coral reef systems on Earth. According to the United Nations Educational, Scientific, and Cultural Organization (UNESCO), which has listed the region and a World Heritage Site, the lagoons and reefs of New Caledonia feature exceptional diversity of coral and fish species, a continuum of habitats from mangroves to seagrasses, and contain the world’s most diverse concentration of reef structures. Intensely beautiful—from Earth or orbiting above—these reefs provide habitat for threatened marine species such as turtles, whales, and dugongs.

Grande Terre is the largest island of New Caledonia, and is a long, narrow island with a tall central spine that gives way to steep slopes in the east and lowland plains in the west. Measuring about 250 miles (400 km) long and only 50 mi (80 km) wide, Grande Terre sits in the Pacific Ocean roughly 830 miles (1,300 km) east of Australia. The island is ringed by a 1,000-mile (1,600-km)-long coral reef. Extending beyond the island, the coral reef forms a huge lagoon that covers about 24,000 square kilometers (9,300 square miles).