"Like most fjords, the Kenai Fjords of Alaska formed by glacial carving. As glaciers melted and sea levels rose, carved coastal indentations filled with water. The walls of a fjord usually plunge deep below the surface of the water."
From the National Geographic book The National Geographic Desk Reference, 1999
(Photograph shot on assignment for, but not published in, "Risk and Reward on Alaska's Violent Gulf," February 1979, National Geographic magazine)