The Arctic Ocean is the smallest, and shallowest of the world's five major oceans. It occupies a roughly circular basin and covers an area of about 14,056,000 km2 (5,427,000 sq mi), almost the size of Russia. The coastline is estimated to be 45,390 km (28,200 mi) long.
Surrounded by the land masses of Europe, North America, Greenland, and by several islands, it is partly covered by sea ice throughout the year, and almost completely in the winter months.
The ocean is virtually icelocked from October to June, and ships are subject to superstructure icing from October to May. Before the advent of modern icebreakers, ships sailing the Arctic Ocean risked being trapped or crushed by sea ice.
