Under the United Nations Convention on the Law of the Sea, foreign vessels and aircraft have the freedom of navigation and overflight to cross the strait of Gibraltar in case of continuous transit.

[12] Exposed bedrock surfaces, coarse sediments and local sand dunes attest to the strong bottom current conditions at the present time.

[citation needed] Around 5.9 million years ago, the connection between the Mediterranean Sea and the Atlantic Ocean along the Betic and Rifan Corridor was progressively restricted until its total closure, effectively causing the salinity of the Mediterranean to rise periodically within the gypsum and salt deposition range, during what is known as the Messinian salinity crisis.

[citation needed] After a lengthy period of restricted intermittent or no water exchange between the Atlantic Ocean and Mediterranean basin, approximately 5.33 million years ago,[13] the Atlantic–Mediterranean connection was completely reestablished through the Strait of Gibraltar by the Zanclean flood, and has remained open ever since.

It is believed that the Rock of Gibraltar may have been one of the last outposts of Neanderthal habitation in the world, with evidence of their presence there dating to as recently as 24,000 years ago.

On 5 August 1936 the so-called Convoy de la Victoria was able to bring at least 2,500 men across the Strait, breaking the republican blockade.

[21] Those talks led to nothing constructive happening, but in April 2021 ministers from both countries agreed to a joint intergovernmental meeting to be held in Casablanca in the coming months.

[22][23] Earlier, in January 2021, the UK government had studied plans for a tunnel to link Gibraltar with Tangiers that would replace the Spanish-Moroccan project that until then had had no tangible results after over 40 years of discussions.

The balance of the water flow is eastwards, since the evaporation rate within the Mediterranean basin is higher than the combined inflow of all the rivers that empty into it, plus the total precipitation of rain or snow that falls on it.

On the Atlantic side of the Strait, a density boundary separates the Mediterranean outflow waters from the rest at about 100 m (330 ft; 55 fathoms) depth.

These waters flow out and down the continental slope, losing salinity, until they begin to mix and equilibrate more rapidly, much farther out at a depth of about 1,000 m (3,300 ft; 550 fathoms).

The Mediterranean outflow water layer can be traced for thousands of kilometres west of the Strait, before completely losing its identity.

During the Second World War, German U-boats used the currents to pass into the Mediterranean Sea without detection, by maintaining silence with engines off.

All these boats had to navigate the British-controlled Strait of Gibraltar where nine U-boats were sunk while attempting passage and 10 more had to break off their run due to damage.

When large tidal flows enter the Strait and the high tide relaxes, internal waves are generated at the Camarinal Sill and proceed eastwards.

The United Kingdom claims 3 nautical miles (5.6 km; 3.5 mi) around Gibraltar on the northern side of the Strait, putting part of it inside British territorial waters.

As this is less than the 12 nautical miles (22 km; 14 mi) maximum, it means, according to the British claim, that part of the Strait lies in international waters.

[32] This proposal would however have devastating effects on the local climate and ecology [citation needed] and would dramatically change the strength of the West African Monsoon.