Which sea is connected to the Atlantic Ocean by the Strait of Gibraltar?

The Mediterranean Sea is connected to the Atlantic Ocean by the Strait of Gibraltar.

The strait is a narrow waterway between southern Spain and northern Morocco, with Gibraltar on its northern side. At its narrowest point, Europe and Africa are only about 14.2 kilometers apart. The strait provides the Mediterranean's direct connection to the Atlantic and is one of the world's major maritime routes.

Water exchange through the strait has a distinctive two-layer pattern. Less-salty Atlantic surface water flows eastward into the Mediterranean, while denser, saltier Mediterranean water flows westward at depth. Because evaporation is high across the Mediterranean basin, this exchange is essential to its water balance and influences circulation far into the Atlantic.

The name Gibraltar comes from the Arabic Jabal Tariq, or “Mountain of Tariq,” referring to the commander Tariq ibn Ziyad. Ancient writers called the surrounding headlands the Pillars of Hercules. The strait also has deep geological importance: after the Mediterranean nearly dried during the Messinian salinity crisis, the Atlantic connection was restored about 5.33 million years ago in the Zanclean flood.