The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Europe and Anatolia, on the south by North Africa, and on the east by the Levant. It covers an area of approximately 2.5 million square kilometers and has an average depth of 1,500 meters. The sea was the superhighway of transport, trade, and cultural exchange for ancient civilizations like the Phoenicians, Greeks, and Romans. Geologically, it is the remnant of the ancient Tethys Ocean. It is characterized by its distinct 'Mediterranean climate'—warm, dry summers and mild, wet winters. Today, it is one of the busiest shipping lanes in the world and a major global tourism destination, though it suffers from heavy plastic pollution and declining fish stocks.