The Cerro del Tambor trail and its former positions of the Spanish Army

The Strait of Gibraltar, which connects the Atlantic Ocean with the Mediterranean Sea, is a place of great strategic importance.

The old tunnels and bunkers of Europa Point, on the south side of the Rock of Gibraltar
A Spanish bunker from the time of World War II next to the Guadiaro River, in Cádiz

As a result, during World War II, the Spanish coast closest to the Strait was fortified, with over 500 bunkers constructed to prevent a possible invasion, whether German or Allied. These Spanish Army positions included coastal artillery batteries, searchlight batteries to illuminate artillery fire, command posts, and other fortifications—a defensive network known as the "Muralla del Estrecho" (Strait Wall).

In their latest video, Aventuras Entresierras (an excellent YouTube channel that I highly recommend you subscribe to) has done a mountain route starting in Huerta Grande, very close to El Pelayo, in the municipality of Algeciras (Cádiz), following the Cerro del Tambor trail, which passes by some old positions of the Strait Wall (the video is in Spanish but has an English audio track; you can activate it in the bottom bar of the player):

Below you can see some screenshots from this video, as a preview. We begin with the searchlight battery on Cerro del Tambor, a position originally intended to illuminate targets for coastal artillery. Today it has been converted into a beautiful panoramic viewpoint.

The Cerro del Tambor Wind Farm, located between Algeciras and Tarifa, is marked by a sign warning that it is military property and that access is prohibited, as it was built on land owned by the Ministry of Defense under a concession agreement.

The remains of an old artillery battery in Guadalmesí, in the municipality of Tarifa. As we can see in the video, the battery is abandoned and all the gun emplacements are disarmed.

The Guadalmesí Tower, in the background, and the buildings that served as quarters for the troops of one of the batteries in the area. The aforementioned tower was built in 1588, during the reign of Philip II, to monitor the passage of ships through the Strait of Gibraltar. The battery buildings date from the 20th century.