South Island

Two huge pieces of the Earth's crust push together here.

Their pushing lifted up the Southern Alps.

The Earth's outer shell is broken into giant plates. Under the South Island, the Pacific Plate and the Indo-Australian Plate meet along a long crack called the Alpine Fault. UNESCO says this is one of only three parts of the world's major plate boundaries found on land.

As the plates collide, they push up the Southern Alps. Ice ages shaped the land too: glaciers carved deep fiords along the coast and troughs that are now filled with lakes.

In UNESCO's description, the Alpine Fault divides the south-west region and marks the contact zone of the Indo-Australian and Pacific plates, one of only three segments of the world's major plate boundaries exposed on land. The plate collision constructs the Southern Alps, which reach nearly 4,000 m within 30 km of the Tasman Sea.

Glaciation, past and present, dominates the landscape: 15 fiords indent the Fiordland coast, a sequence of 13 forested marine terraces along the Waitutu coast has been uplifted more than 1,000 m over the past million years, lake-filled glacial troughs line the south-eastern margin, and moraines of ultramafic rock reach the Tasman coast.

Lake Matheson was made by a glacier.

On still days, the lake is like a mirror.

Lake Matheson, in the photo, was made by Fox Glacier. During the last ice age, the glacier spread across the coastal plain toward the sea and dumped huge piles of rock. When it pulled back from its last big advance, about 14,000 years ago, the hollow it left filled with water.

The Department of Conservation says the lake is famous for reflecting Aoraki/Mount Cook, Mount Tasman and the Southern Alps, best at dawn and dusk on a sunny, windless day.

According to the Department of Conservation, Lake Matheson/Te Ara Kairaumati formed when Fox Glacier/Te Moeka o Tūawe retreated from its last significant advance about 14,000 years ago; during the last major ice age the glacier had spread across the coastal plain toward the sea, depositing large piles of rock, and the basin it left filled with water.

The lake's dark water, colored by organic matter from the forest floor, makes it famous for mirror reflections of Aoraki/Mount Cook, Mount Tasman/Te Horokōau and the Southern Alps; reflections are best at dawn and dusk on sunny, windless days. Long-finned eels are abundant in it, and DOC notes the lake is a customary food-gathering place for Ngāi Tahu.

The kea is a parrot that lives in the mountains.

The takahē is a bird that cannot fly. All the wild ones live in the island's southwest.

New Zealand's animals evolved in isolation for a very long time, with no mammal predators. UNESCO says that is why its animals are so unusual.

In the island's southwest live the kea, which UNESCO calls the only alpine parrot in the world, and the takahē, a rare flightless bird whose whole wild population lives there. Some of the area's southern beech and podocarp trees are more than 800 years old.

UNESCO credits Te Wāhipounamu's fauna to long evolutionary isolation and the absence of mammalian predators. The area holds the entire wild population of the endangered takahē (Notornis mantelli), the entire South Island subspecies of brown kiwi, the rowi (Apteryx rowi), New Zealand's rarest kiwi, and the main remaining populations of mohua, kākā and kākāriki. The kākāpō survived in Fiordland until the early 1980s and is now thought extinct on the mainland.

Two-thirds of the area is covered by southern beech and podocarps, some over 800 years old, and its temperate rainforests show plant succession on surfaces left by retreating glaciers.

The weather can change fast here. Check it before you go.

Bring bug spray too. Sandflies can bite!

The Department of Conservation warns that New Zealand weather changes quickly, so check the forecast before you go and be prepared. At Lake Matheson, sandflies can be fierce, so bring insect repellent.

There are no rubbish bins on the track: take your rubbish home. Boats of any kind are not allowed on the lake, and drones need a permit.

For the Lake Matheson/Te Ara Kairaumati walk (a 4.4 km loop, about 1 hour 30 minutes, with a wheelchair-accessible first section to Jetty Lookout), the Department of Conservation advises checking the forecast because New Zealand weather changes quickly, bringing insect repellent against sandflies and carrying out all rubbish. No watercraft are permitted on the lake, flying drones without a permit is prohibited, and dogs are not allowed.