Earth is nicknamed the Blue Planet because approximately 70% of its surface is covered with water. Most of that water is found in the oceans. There are 5 oceans - the Pacific, Atlantic, Indian, Arctic, and Southern Oceans. The Pacific Ocean is the largest of the world's oceans. The Southern Ocean surrounds Antarctica, and is composed of waters from the southern portions of the Atlantic, Pacific, and Indian Oceans. Both the Arctic and Southern Oceans are covered with vast expanses of sea ice during the winter. The ice melts in the summertime except in the coldest parts of these oceans, where the ice does not thaw in the summer.

The average depth of the ocean is 4, 267 meters (14,000 feet). The deepest part of the ocean is located in the western Pacific and is part of the Mariana Trench. This deep part of the ocean is called Challenger Deep. Here the ocean is 11,030 meters (36,200 feet) deep.

The following video provides an overview of the world's oceans. It explores the biodiversity of the world's oceans and seafloor topography. It introduces the concepts of ocean pollution and the overuse of ocean resources, and describes the impacts of human activities on ocean ecosystems.