Surrounded by Mount Phillips, the Lion, the Elephant and the highest of all, Mitre Peak (1690 m) lies one of most visited sites in New Zealand: Milford Sound. Carved out by ancient glaciation and now filled with ocean and freshwater, the famous fiord stretches 15 km in length and reaches depths of up to 400 m. Since it is directly exposed to strong northwest winds of the Tasman Sea, Milford Sound is considered to be one of the wettest locations on earth, alongside places in India, China and around the equator. Fiordland’s mountains act as barriers causing orographic rainfall of up to 8000 mm annual precipitation.
Hundreds of temporary or permanent waterfalls such as the Bowen or Stirling Falls can be observed throughout the park. The heavy amount of incoming fluid created a thick freshwater layer on top of the salty seawater. The layer changes light refraction conditions causing deep sea species such as the black coral to be observed in much lower depths. The Underwater Observatory gives best opportunities to do so.
In 1912, Milford Sound was named by John Grono in reference to Milford Haven in Wales. The Maori were believed to have discovered the fiord’s beauty over 1000 years earlier calling it "Piopiotahi". The piopio, a an extinct bird species, was believed to have lived in the rainforest emerging on the fiord’s slopes. According to the Maori, the piopio flew over the fiord after Maori-hero Maui’s death.
Since the Homer Tunnel (1.2 km) was opened in 1954, Milford Sound remains as the only fiord that is reachable by car.