Geographically, the Mediterranean Sea is defined by its borders against southern Europe, northern Africa and western Asia. Blocked by the Strait of Gibraltar (known in past times as the Pillars of Hercules) in the west, the Black Sea near the Dardanelles and the Bosporus in the east, the Mediterranean is occasionally considered to include the Sea of Marmara. Bordering nations include: Morocco, Algeria, Tunisia, Libya, Egypt, Israel, Lebanon, Syria, Turkey, Greece, Albania, Montenegro, Bosnia and Herzegovina, Croatia, Italy, France and Spain. It is 3,900Km long, at maximum 1,600Km wide and has a maximum depth of 4,400m. The shores are chiefly mountainous, and the major rivers which flow into it are the Po, Rhône, Ebro, and Nile.
Around six and a half million years ago, the Mediterranean Sea did not deserve the title. No body of water, save a series of craterous salt lakes (denoted by the build-up of mineral of mineral salts at a significant depth under the sea bed) separated Europe from Africa. All that could be seen of the region’s current landform was the occasional volcanic island (Corsica, Sardinia and some of the Greek Cyclades). It was largely a barren wasteland, hot and uninhabitable by any significant quantities of life. Lithospheric plate motion, however, created one of the most abrupt transformations in the history of the Earth.
The modern Mediterranean Sea was formed when the Atlantic Ocean overflowed a precipice (situated between Morocco and Gibraltar) around fifty times the height of Niagara Falls, flowing for an entire century before the desolate basin was filled. There is geological evidence to suggest that several overflows occurred, but climate changes were sudden: what was previously a harsh wasteland now gave way to verdancy and an abundance of wildlife, although the Mediterranean continues to be reliant on the flow of waters from the Atlantic. Even in today’s relatively cool climate, 1610 cubic Km of water is evaporated from the water’s surface every year, although it is this cycle of evaporation and precipitation which fuels the Mediterranean’s ecosystems. Water flows in from the Atlantic at a rate of 4Km/h; this is due to the relatively tight space between the North African coast and Gibraltar. In places, the sea is only 300m deep.
Few plants or animals survived the great desiccation which afflicted the Mediterranean. Most species, therefore, migrated into the region (from Asia, Africa, Europe and the Atlantic Ocean) in search of sustenance or more hospitable conditions. The Mediterranean region also survived later periods of cooling which stripped tropical vegetation from the north and the desertification of Africa from the south. These periods of cooling saw the Mediterranean become a closed basin, perpetually becoming more and more saline as the Atlantic currents were cut off. Nowadays, many types of whales are common (sperm whales, pilot whales and killer whales), although dolphins (bottlenose and common) are far more abundant. Leatherback and loggerhead turtles have been sighted, as have seals (especially monk seals). 557 fish species have been sighted in the Mediterranean; while the exact biodiversity of the Mediterranean Sea and its coastal rim is not known, reliable estimates suggest that only half of the species present (either permanently or due to migratory patterns) have been documented. These estimates further project that around 15,000 species of plants and animals are present, although wide-scale tourism threatens many habitats and almost all species present in the ocean face some form of threat.
Humankind arrived in the Mediterranean two million years ago, migrating north-west from Ethiopia. Remains found in Algeria show that they were more stooped, heavier-browed and larger-jawed than homo sapiens: these first arrivals were Neanderthals. Their exact migration pattern is not known - it is reasonable to assume (based on carbon dated settlements and artefacts) that different tribal groups migrated from different directions, immediately west across the Strait of Gibraltar, east around the Levant and Turkey or even directly between islands. Only crude hunting tools were used by this stage, but these tools were progressively refined and within a geologically short period of time, the Mediterranean would serve as the cradle for much of modern human civilisation. Hence, the name: ‘Middle Earth.’
Archaeology: the Definitive Guide, various authors
The First Eden: the Mediterranean World and Man, David Attenborough