The Great Barrier Reef is sometimes described as the Earth’s largest living organism, but it is much more than that.

There is nothing else on the planet like it: more than 3000 individual reefs and 1000 islands spread across an area stretching 2300 kilometres. It is the only natural wonder you can see from space.

The Great Barrier Reef stretches 2300km from the Torres Strait in the north down to Fraser Island, south of Gladstone.

But 2016 has been a bad year for the reef – the worst on record. It faces multiplying pressures, one of them planetary and existential, others local and interlinked. Its world-famous coral colonies have been the hardest hit, though there has been public confusion over the extent of the damage.

Senior scientists say it is now crunch time, warning another serious bleaching event is likely within five years, if not sooner. If urgent action isn’t taken, the reef as we know it could cease to exist.

As the Australian government prepared to update the UNESCO World Heritage Centre on the steps the country has promised to maintain its world heritage status, Fairfax Media travelled the reef to investigate the threats to its health.

We talked to people who study it, care for it, work and rely on it, and asked what it will take to save it.

• OVERVIEW
• WARMING
• INDUSTRY
• PEOPLE
• WATER
• MINING