The Alcazaba, Castle and Walls of the Cerro de San Cristóbal in the Spanish city of Almería is one of the most important Andalusian monumental and archaeological sites on the Iberian Peninsula. Its almost thousand years of history has allowed us to know the evolution experienced in civil and military architecture during the Arab domination in Al-Andalus, due to its construction in different phases and periods, such as the castle and towers of the Christian late medieval period (15th-16th centuries), as well as the origin and evolution of the city (with a total perimeter of the entire fortification, according to the Tourist Office of Almeria, of 1430 metres, including the late medieval castle, the citadel preserved today and the rest of the outer walls).

Situated on an isolated hill, the Alcazaba is a solid and extensive fortress with walls more than three metres wide and five metres high, forming an enclosure closed in on itself, but connected with the walls of the city walls that form and give meaning to its own development, within a more complex unit, such as the fortification of the city, in which the ravine of La Hoya and the hill of San Cristóbal maintain a direct connection with the Alcazaba, both physically and visually, creating a complex of extraordinary magnitude. The Alcazaba-Castle is connected to the south with the city, and to the north with the Cerro de San Cristóbal, which defines a unique space of unquestionable cultural interest.

It is one of the best preserved citadels today, being the second most extensive Arab citadel on the Iberian Peninsula in terms of its construction enclosure from the Muslim period and the second of all those that are preserved today.

The city of Almería was founded in the 10th century by the Caliph Abderramán III as a defensive watchtower for the then prominent city of Bayanna, now Pechina. The city had a castle-fortress or alcazaba and a wall that surrounded the entire medina and the suburbs. The Alcazaba is visible from any point in the city, especially its imposing keep, and is a very pleasant place to visit.

It was in 955 that the first caliph of Al-Andalus, Abd al-Rahman III, ordered the Alcazaba to be built on the remains of an earlier fortress. Sandstone from a nearby quarry, later known as the Caliph's Quarries, was used. The enclosure has three distinct parts: two of Arab origin and style and a later Christian one.

The wall of the Cerro de San Cristóbal, better known as the walls of Jayrán, is what remains standing today of the ancient wall that surrounded the entire city and was built by the first king of the Taifa of Almería, Jayrán. Although more sections of the wall have been found in other areas of Almería, such as in the nearby underground shelters of Almería, this is the only part that has always been found in the open air and has not subsequently been discovered in a state of ruins.