Mediterranean Sea million years ago (mya) in less than two years by the Zanclean flood. Water poured in from the Atlantic Ocean through a newly breached gateway now called the Strait of Gibraltar at an estimated rate of about three orders of magnitude (one thousand times) larger than the current flow of the Amazon River. The Mediterranean Sea has an average depth of and the deepest recorded point is in the Calypso Deep in the Ionian Sea. The coastline extends for . A shallow submarine ridge (the Strait of Sicily) between the island of Sicily and the coast of Tunisia divides the
Command of the sea Great Britain accepted the principle in 1805; Russia, in 1824; and the United States (tacitly) in 1894. Many treaties, including the Treaty of Versailles, have dealt with the open seas, and currently the United Nations Convention on the Law of the Sea formalizes this freedom. Historically, many powers attempted to extend command of the sea into peacetime, imposing taxes or other restrictions on shipping using areas of open sea. For example, Venice claimed the Adriatic, and exacted a heavy toll from vessels navigating its northern waters. Genoa and France each claimed portions of the western Mediterranean. Denmark and Sweden claimed