Rennell Island looks like a big flat table rising out of the Pacific Ocean. Around its edges are ancient coral cliffs, while the interior is covered in thick forest. In the eastern part of the island sits Lake Tegano, the largest lake in the whole Pacific Islands region. It is a saltwater lake - connected to the ocean underground - and home to many species found nowhere else on Earth.
Because Rennell is so remote and hard to reach, its forests have stayed almost untouched for thousands of years. Ancient trees tower over the canopy, and birds that have never had to fear humans are still quite tame. Scientists have discovered dozens of plant and animal species on Rennell that live nowhere else in the world.
The Rennellese people have a deep knowledge of every plant, bird, and fish on their island. They have traditional rules - called 'customary management' - about which areas of forest can be used and which must be left alone. This ancient wisdom has helped the island stay so healthy for so long.