Fjord

A fjord is like a long, skinny lake that is surrounded by really tall mountains. The water in the fjord is usually very cold and dark because the mountains block the sun from reaching deep down into the water. Fjords are formed when glaciers (which are big blocks of ice) move across the land and carve out a valley in between the mountains. When the glaciers melt, the valley fills up with water from the ocean and becomes a fjord. Fjords are really cool because they are not like regular lakes or rivers - they are like a secret hidden world inside the mountains!