Great Barrier Reef

Great Barrier Reef

Great Barrier Reef

Great Barrier Reef, complex of coral reefs, shoals, and islets in the Pacific Ocean off the northeastern coast of Australia that is the longest and largest reef complex in the world. The Great Barrier Reef extends in roughly a northwest-southeast direction for more than 1,250 miles (2,000 km), at an offshore distance ranging from 10 to 100 miles (16 to 160 km), and its width ranges from 37 to 155 miles (60 to 250 km). The Great Barrier Reef has an area of some 135,000 square miles (350,000 square km), and it has been characterized, somewhat inaccurately, as the largest structure ever built by living creatures.