Milford Sound / Piopiotahi

Long ago, rivers of ice called glaciers filled these valleys.

The ice scraped the rock and made deep valleys with steep sides. When the ice melted, the sea came in.

DOC explains that the U-shaped valleys and steep, bare walls around Milford Sound were made by glaciers grinding and rounding the hard Fiordland rock, such as gneiss, diorite and granite. UNESCO says the whole region was shaped by one glaciation after another.

The mountains keep going down under the water, to depths of up to 265 meters. Near the Homer Tunnel on the road in, the ice carved a cirque, a steep-walled bowl like an amphitheater.

Per DOC, the Milford Road begins on ridges of rock debris left at the side of the glacier that once filled Lake Te Anau, and the U-shaped valleys and sheer walls of hard Fiordland rock (gneiss, diorite, granite) were formed by glacial grinding and rounding; just before the Homer Tunnel the road enters a cirque basin. Under the water the mountains continue to depths of up to 265 m.

UNESCO's statement describes Te Wāhipounamu as showing classic examples of the tectonic, climatic and glacial processes that shape Earth: the Alpine Fault, the contact zone of the Indo-Australian and Pacific plates, divides the region, and glaciation, past and present, dominates the landscape.

It rains a lot at Milford Sound.

Rainwater flows into the sea and floats on top. It is brown like tea. Under it, special sea animals grow on the rock walls.

Milford Sound is one of the wettest places in New Zealand, with up to 7 meters of rain a year. So much fresh water pours in that it makes a permanent layer floating on top of the salty sea. Material washed out of the forest stains this layer the color of tea.

Below it, in a band 40 meters thick, unusual sea life grows on and around the sheer rock walls. DOC says divers come here to see black coral, which Fiordland's fiords are famous for.

DOC: very high rainfall, up to 7 m a year, creates a permanent freshwater layer on the sea surface, stained a tea color by material washed out of the forest. Below it a concentrated 40 m band of unusual marine life grows on and around the sheer rock walls.

On the inner northern wall, deep-water invertebrates fixed to the rock dominate: encrusting tubeworms, sponges, soft corals, colonial sea squirts, black coral and anemones. The Piopiotahi Marine Reserve is one of the most popular places in Fiordland to dive and see the black corals for which the fiords are famous.

Seals, octopus and fish live in the water. Sometimes dolphins swim by.

Ferns and mosses grow in the wet forest. A cheeky mountain parrot called the kea lives near the road tunnel.

Divers in the marine reserve may see stingrays, crayfish, octopus, seals, sharks and more than 100 other kinds of fish. Toward the open sea, divers are often surrounded by schools of butterfly perch, and a few bottlenose dolphins live there too.

On land, tree ferns, mosses and ferns thrive in the wet forest of silver beech. Kea, New Zealand's mountain parrots, are often seen around the Homer Tunnel, and DOC warns that they are cheeky, so watch your belongings!

The 690 ha Piopiotahi Marine Reserve (1993) runs 16 km along the northern side of the sound, from Milford Sound village to Dale Point at the Tasman Sea, over mostly deep muddy basin, a large section of deep reef and a small strip of shallow rock wall. Divers may meet stingrays, crayfish, octopus, seals, sharks and more than 100 other fish species; toward the sea there are schools of butterfly perch, hundreds of rock lobster and occasional bottlenose dolphins.

On the descent to the sound, occasional rimu rise above silver beech, with tree ferns, shrubs, mosses and ferns. Kea are often seen around the Homer Tunnel, and the rare rock wren lives among boulders nearby. UNESCO notes that the World Heritage Area is home to the kea and the endangered takahē.

Long ago, Māori people came here to gather a green stone.

Later, a sailor gave the fiord its English name. Today a road and a tunnel lead visitors there.

The Māori name Piopiotahi means "one native thrush", after the piopio, a bird now thought to be extinct. Early Māori gathered greenstone here and carried it away by sea or along an inland route over what is now the Milford Track.

The English name came from a Welsh sealing captain, John Grono, who named it after his birthplace, Milford Haven. In 1878 a Scottish sealer, Donald Sutherland, built three thatched huts here. Work on the Homer Tunnel, which carries the road through the mountains, began in 1935 and was finished in 1954.

DOC records that early Māori gathered kokotakiwai (greenstone) here, moving it mainly by sea to Murihiku (Southland) or inland over Omanui (McKinnon Pass) along the line of today's Milford Track; permanent settlements lay in the Hollyford Valley and around lakes Manapōuri and Te Anau. The name Piopiotahi means "one native thrush", after the piopio, which declined after mammal predators were introduced and is now thought to be extinct.

The sealing captain John Grono named the sound after his birthplace, Milford Haven in Wales. Donald Sutherland, its first European resident, built three thatched huts in 1878; with Quintin Mackinnon he later cut the Milford Track. William Homer found the Homer Saddle in 1889, and the Homer Tunnel, begun in 1935 and delayed by difficult conditions and the Second World War, was completed in 1954.

People drive a long road to get there. Then they walk by the water or take a boat.

Bring a raincoat. Stay with a grown-up near the water.

The Milford Road from Te Anau takes about two hours to drive without stops. Weather, rock falls and, in winter, snow and avalanches can close the road or cause delays, so check before you go. Drones are not allowed without a permit.

The short Milford Foreshore Walk is an easy, wheelchair-friendly loop through beech forest and along the shore, with some of the best views of Mitre Peak. There may be a lot of sandflies on the walk!

DOC advises allowing about 2 hours for the Milford Road without stops, expecting closures and delays from weather, rock falls and winter snow and avalanches, and checking the road status first; freedom camping within 200 m of the road is not allowed, and drones need a permit. Te Anau is the nearest town with facilities.

DOC also notes that a large earthquake or tsunami is extremely unlikely during a visit but would leave few options: drop, cover and hold during shaking, and if it is long or strong, or a landslide is seen or heard, move up and away from the water.