Coral Greenhouse, John Brewer Reef

The sculpture

The greenhouse stands 12 m tall on the seabed at about 16 m. It holds the Guinness World Record for the largest underwater art structure. It is built from pH-neutral cement and corrosion-resistant stainless steel, with an open frame that lets light in and gives fish and coral somewhere to settle.

Inside and around it are figures modelled on local school children, tending coral in pots and on work benches, plus coral planter boxes and floating “trees” based on local species. The idea is that coral grows over the pieces and they slowly become part of the reef.

Ocean Sentinels and the reef

A short swim away, in shallower water, are the Ocean Sentinels: sculptures of Australians known for their work in marine science and conservation. Snorkellers use the shallow areas of about 4–6 m, while the greenhouse itself, in 12–18 m, is best seen on scuba. The surrounding coral reef is close enough to visit on the same dive.

The installations are in a sheltered part of John Brewer Reef, chosen to keep visitors out of strong currents. Citizen scientists have recorded more than 240 fish and invertebrate species on the reef, including whitetip reef sharks.

Rules and history

The sculptures are public art inside the Great Barrier Reef Marine Park and are free for recreational visitors. Treat them like coral and don’t touch. The area is a Conservation Park Zone, where limited fishing is allowed, but fishers are asked to stay at least 50 m from the sculptures.

The reef is named after the troop ship John Brewer, which ran aground here in 1842. It was also once home to the world’s first floating hotel, which has since been towed away.