Fjords are formed when glaciers cut through existing rock during an ice age. In Norway and other Western countries, the rock is otherwise resistant to erosion, which allows the fjords to stay intact.
Most fjords have a strong current caused by the rise at the mouth. Many fjords in Norway and New Zealand are home to large coral reefs.
Fjords vary in length and depth. The world's longest fjord is Scoresby Sund in Greenland, which is 350 km long. Skelton Inlet in Antarctica is the world's deepest, at 1,933 meters deep.
For a body of water to be considered a fjord, it must have been created by glacial activity. Other fjord-like bodies of water, such as the deep bays in New England, aren't technically fjords.
Norway's fjords are sometimes referenced in pop culture, most famously in a popular Monty Python sketch. When a disgruntled pet shop customer tries to return a dead Norwegian Blue parrot, the shady owner insists that the bird is not dead, but is "pining for the fjords" instead.
