Following is a transcript of the video. Narrator: This is the Great Barrier Reef, and it's dying. Less than 20 years ago, the world's largest living structure looked like this, and this.

For decades, the Great Barrier Reef has enjoyed World Heritage Status and been synonymous with diving, tourism and with Australia. But in June of this year, UNESCO threatened to downgrade the Great ...

Stretching over 1,200 miles, Australia's Great Barrier Reef is the largest structure on Earth built by living organisms. Even for its size, it houses an incredible biodiversity -- literally ...

In 2016 and 2017, marine heat waves caused by climate change resulted in mass bleaching, which killed about half of the corals on the Great Barrier Reef, along with many others around the world.

Professor Ove Hoegh-Guldberg describes the Great Barrier Reef as "the Manhattan of marine ecosystems”. Coral reefs are vitally important nursery grounds for fish and other marine life.

Bleaching of the coral in the Great Barrier Reef, north-east Australia which is caused by global warming The Great Barrier Reef became a recognised area of ecological importance when it was ...