While craters and calderas are topographic depressions formed by eruptions and geysers are hydrothermal vents heated by magma, a fjord is purely a product of ice. During the ice ages, massive glaciers carved “U-shaped” valleys deep into the Earth’s crust. When the glaciers melted and sea levels rose, these valleys were flooded by the ocean. Fjords are characteristic of coastlines like Norway, Chile and New Zealand. They represent the power of erosional glaciation, distinguishing them fundamentally from the endogenic (internal) forces that create volcanic landforms.