Fiords, also spelled "fjords," are deep, narrow inlets of the sea that are typically surrounded by steep cliffs or mountains. They are formed by the glacial erosion of valleys, where glaciers carve out U-shaped valleys that later fill with seawater as the glaciers retreat. This unique landscape is often found in regions with a history of glaciation, such as Norway, New Zealand, and Chile. The water in fiords is usually quite deep, and they can be several hundred meters deep in some areas. The steep sides of fiords create dramatic scenery, making them popular destinations for tourists and nature enthusiasts. Wildlife, including seals and various bird species, often thrives in these rich marine environments.