This 3D view of the Bering Sea shows the shallow waters of the continental shelf between Alaska and Asia, the deep Aleutian Trench and adjacent island arc, with the Kamchatka Peninsula on the horizon.

The largest mountain on Earth is the volcano Mauna Kea, Hawaii, which rises 9,000 metres (24,000 feet) . from its base on the floor of the Pacific Ocean. Many more volcanoes rise from the ocean floor, but do not reach the surface - these are called seamounts. A guyot is a flat-topped seamount.

The volcanoes of the Hawaiian island chain rise up to 9,000 metres. from the ocean floor.

The continents are fringed by relatively shallow areas known as the continental shelf, lying up to 300 metres (820 feet) below the sea surface. At times in the past when sea levels were lower, large parts of the continental shelves would have been dry land, home for long periods to plants and animals. At the edge of the continental shelf, the continental slope leads down to the ocean floor, in most places below 2,000 metres (5460 feet).

The continental shelf off northwest Europe extends beyond the British Isles.

Much of the deep ocean floor consists of the flattest places on Earth - the abyssal plains. These plains are punctuated by seamounts, ridges, plateaux, fracture zones and deep trenches. Spreading ridges run across the ocean basins, marking the locations where the Earth's tectonic plates are moving apart (diverging). The ocean trenches show where plates are meeting (converging), with the oceanic crust sinking down under an adjacent area of continental crust.

Iceland straddles the Mid-Atlantic Ridge (shown in red).

The Mid-Atlantic Ridge breaks through the sea surface at the island of Iceland, while the deepest part of the Ocean is in the Marianas Trench, which reaches a depth of 11,034 metres (30,000 feet). Long fracture zones extend from the mid-ocean ridges as parts of the plate move at different speeds. Very many fractures run out from the steep Mid-Atlantic Ridge, while several long fractures can be seen running across the Pacific from the East Pacific Rise.