Between southern Europe, North Africa and Western Asia, there is a vast water area of about 2.51 million km2, which is the largest land sea in the world - the Mediterranean Sea. It is about 4000 km long from east to west, 1800 km wide from north to south, and only 13 km wide at the narrowest point in the West. 5km。 It has an average depth of 1541m and a maximum depth of 5121m. From a high altitude, the Mediterranean sea looks like a long and narrow spinner, with the Suez Canal and the Strait of Gibraltar at both ends.
The Mediterranean is not a complete sea area. There are many peninsulas and islands in the sea. In the north, there are three major peninsulas in southern Europe and Sicily, Sardinia, Corsica and other islands in the deep sea of people. With the peninsula and the islands in the sea as the boundary, they divide the Mediterranean Sea into seven "sub" seas, including Ligurian Sea, Tyrrhenian Sea, Adriatic Sea, Ionian Sea and Aegean Sea. The magnificent Alps are towering on the North Bank of the Mediterranean Sea, and the vast Sahara desert is on the south bank. Only the Nile and the Po rivers on the north and south banks have fresh water.
Due to the influence of the climate in the Mediterranean region, the summer is very hot and dry, and the sea water evaporation is very large. It is calculated that only the evaporated seawater in a year can reduce the whole sea level by 1. 5m。 You may wonder: will intense evaporation dry up the Mediterranean sea day by day? This fear is superfluous. What is the reason? It turned out that this was due to the Atlantic Ocean and the Black Sea. The Dardanelles Strait, Bosporus Strait and Gibraltar Strait, which connect the Mediterranean and the ocean, were both navigation channels and irrigation and drainage channels.
The sea water with low salinity in the Black Sea and the Atlantic Ocean can pass through the surface of the Strait respectively and flow into the Mediterranean, while the saltier and heavier sea water in the Mediterranean is discharged into the Black Sea and the Atlantic respectively from the deep layer of the Strait to keep the circulation smooth. In this way, the sea water in the Mediterranean will not become less and less, nor will it become more and more salty. There are two ways from the Mediterranean to the ocean: one is in the East, and ships can lead to the Indian Ocean through the Suez Canal and the Red Sea; The other one is at the western end, and it can go directly to the Atlantic Ocean along the Strait of Gibraltar.
Since ancient times, it has been an important channel for coastal countries. The Mediterranean once gave birth to splendid ancient civilizations, from which the ancient civilizations of Egypt, Greece and Rome spread to all parts of the world.