What is Underwater?
An '''underwater environment''', otherwise known as an '''undersea environment''' or simply '''underwater''' or '''undersea''', is a place below the [[surface]] of a [[body of water]] such as an [[ocean]], [[sea]], [[lake]], [[pond]], or [[river]]. Most of the planet [[Earth]] is covered by water. The bottom of the ocean is called the seabed. Most of the [[seabed]] is between {{convert|4000|and|5500|m}} below the surface of the ocean. Just like the Earth's [[dry]] [[land]], the seabed also has [[mountain]]s, [[valley]]s and [[flat]] [[plain]]s, although they are covered with water. The [[deep]]est part of all the world's oceans is a place called the [[Challenger Deep]], which is in the [[Mariana Trench]]. It is {{convert|10924|m}} under the sea. Although a number of [[human]] activities happen underwater, such as [[underwater diving]] for work or [[recreation]], or even warfare with [[submarine]]s, most of the oceans, especially the deepest parts, have not been [[explore]]d yet. == References == [[Category:Water]] {{geo-stub}}