The Great Barrier Reef of Australia passed away in 2016 after a long illness. It was 25 million years old. For most of its life, the reef was the world’s largest living structure, and the only one visible from space. It was 1,400 miles long, with 2,900 individual reefs and 1,050 islands. In total area, it was larger than the United Kingdom, and it contained more biodiversity than all of Europe combined.