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 sometimes criminal organizations, they fell into disfavor with stronger governments. An annex to the Treaty of Paris (1856) banned privateering. That treaty was an oddity in that it was ratified by relatively few countries, but quickly became the "de facto" law of the sea. A more modern countermeasure, similar to privateering, was the use of submarine warfare by Germany during World War I and World War II to attack allied merchant shipping primarily in the Atlantic Ocean, Mediterranean Sea, and Baltic Sea. During World War II, aircraft also became an effective countermeasure to command of the sea, since ships could