What is Black Sea?
[[File:Black Sea map.png|right|thumb|The Black Sea]] The '''Black Sea''' is a [[sea]] in [[Eurasia]] between [[Europe]], [[Caucasus]], and [[Anatolia]]. Many important rivers flow to the Black Sea, including the [[Don River|Don]], the [[Danube]], the [[Dniester]] and the [[Dnieper River|Dnieper]]. It is connected to the [[Atlantic Ocean]] through the [[Bosphorus]], the [[Sea of Marmara]], the [[Dardanelles]], the [[Aegean Sea]], the [[Mediterranean Sea]] and the [[Strait of Gibraltar]]. The sea is divided by [[Crimea]]. Nine tenths of the Black Sea has no [[oxygen]]. Its water is [[saltwater]] but less salty than the oceans are. During the [[Pleistocene|last ice age]], the Black Sea was a [[freshwater]] lake. == History == In [[Greek mythology]], the [[Jason|Argonaut]]s traveled on the sea. The [[Ancient Greece|ancient Greeks]] set up colonies around the sea because it was important for them to [[trade]] during [[ancient history]]. The [[Gallipoli Campaign]]. during [[World War I]]. was a fight for access to the Black Sea, which was also an important sea during [[World War II]]. == Geology == The Black Sea sits on [[continental plate]]s, which have [[Subduction|subsided]]. It is a geologic [[Basin (geology)|basin]] and so is a genuine [[inland sea]].<ref>{{cite journal|doi=10.1016/S0037-0738(02)00286-5|bibcode=2003SedG..156..149N|title=The Black Sea basin: tectonic history and Neogene–Quaternary rapid subsidence modelling|year=2003|last1=Nikishin|first1=A|journal=Sedimentary Geology|volume=156|issue=1–4|pages=149–168}}</ref> It has a maximum depth of about 2000 m. The Black Sea is the world’s largest basin, and its deep waters do not mix with the upper layers of water that receive [[oxygen]] from the [[atmosphere]]. As a result, over nine tenths of the deeper Black Sea volume lacks oxygen. The upper layers of the Black Seaare fed by large [[river]] systems and so are generally cooler, less dense and less [[salt]]y than its deeper waters, which come from the warm, salty waters of the [[Mediterranean Sea]].