A hidden "lake" of New Zealand

It's a very excited for New Zealand citizens. It's hard to believe there's a hidden lake in New Zealand, a country where lakes take centre stage, from ice-blue glacial tarns to steaming, acidic volcanic pools. Even more surprising, this little-known lake is hidden in plain sight – on an island in one of the country's most famous lakes, where thousands of tourists flock to photograph a single willow tree in the water. But most New Zealanders have never heard of Arethusa Pool, a freshwater lake on the top of Mou Waho Island in Lake Wanaka, in the Otago region of New Zealand's South Island.

As we watched, gentle ripples ruffled the surface of Arethusa Pool, smudging reflections of the fringing native vegetation, so the lake looked like liquid pounamu, the greenstone gem treasured by New Zealand Māori. Two tiny rocky islands, resembling bonsai landscapes, adorned the lake like the upper-most decorations on a tiered wedding cake – for they are islands in a lake, on an island in a lake, on an island in the ocean.

In a country also renowned for epic views, this is up there with the best. Arethusa Pool is a tarn formed by glacial scouring in the last ice age. It appears suspended 150m above Lake Wanaka, which in turn is surrounded by range upon range of serrated mountains, including the spine-like Southern Alps that run the length of the South Island, some still snow-tipped in late spring, others swaddled in folds of cloud. There's no sign of civilisation, no hint of Wanaka township, just a 30-minute boat trip away.

But there's more to this island than breathtaking vistas. Mou Waho, meaning "outer island", is the largest of four significant islands in Lake Wanaka. The 120-hectare bedrock pedestal is also a predator-free sanctuary protecting some of the country's most unusual endemic species, yet it's freely accessible and overnight camping is permitted. It wasn't always like this though, explained Chris Riley of Eco Wanaka Adventure', who has been taking visitors to the island on half-day tours since 2006.