Abderrahmán III ordered the construction of the Alcazaba, over the ruins of an old fortress, in an isolated hill that dominates the bay. Later, it became the palace and fortress of Hairan, the first King of Almería. During many years, it remains in a complete oblivion. In the current Monumental Complex, we can see that it is divided into three different precincts: the first two have a Muslim design, and the third has a Christian one.

The first precinct is dominated by gardens. In the most eastern end, the Saliente Bastion is located, from here you can go up to the esplanade of the Vela Wall, whose name comes from the Vela bell, that announced different events when they were taking place: when ships came into the bay, danger, fire, etc. In the second precinct the city- palace was located, with the mosque, the baths, cisterns, shops, etc. In this part, the ruins of the Arab Palace of Almotacín are located.

The works from the third precinct were ordered by the Catholic Kings. The old cisterns are conserved in its square. The haughty Keep dominates the whole complex. This fortress is linked to the Castle of St. Cristobal by strong walls.