A fjord is a long, narrow arm of the sea that can extend far inland, and is the result of marine inundation of a glaciated valley. Fjords can be extremely deep, so deep in fact that they can extend thousands of feet below sea level.
The enormous glaciers that formed in these valleys were so heavy that they eroded the bottom of the valley far below sea level before they ever floated in the ocean water. After the glaciers melted, the waters of the sea invaded the valleys that had been created by the glacier's passage across the land.
Fjords commonly have winding channels and sharp corners reflecting the movement and shapes of glaciers. In many cases the valley, floored with glacial debris, extends inland into the mountains. (Continue Reading from Encyclopedia Britannica)
Fjords can be found in Norway, Chile, New Zealand, Canada, Greenland, and in Alaska.
Somewhat surprisingly, you can also find large coral reefs at the bottom of some fjords. These reefs are home to several types of fish, plankton and sea anemones. Some of these fjord-bound coral reefs are found in New Zealand, though most are found in Norway.
(Continue Reading from National Geographic)