Drone image showing an exposed reef at low tide, Uluwatu, Bali, Indonesia

Seen here at an extreme low tide, these exposed corals compose part of the reef that creates the storied surf break of Uluwatu, Bali. This Indonesian isle sits deep within the Coral Triangle—a vast region astride the Pacific and Indian oceans that includes the world’s most biodiverse marine zones. Spread across more than 17,500 tropical islands, Indonesia alone contains 18% of the world’s coral reefs and about 70% of coral species, making the country a key front in efforts to preserve these endangered ecosystems.