The area of the city has been populated since prehistory, and the earliest remains belong to Neanderthal populations from the Paleolithic.
Due to its strategic position it was an important port under the Phoenicians, and was the site of the relevant Roman port of Portus Albus, with two near cities called Caetaria and Iulia Transducta, founded by the Romans themselves.
After being destroyed by the Germanic Barbarians and their Vandal allies, the city was founded again in 711 by the invading Moors, as the first city created by the Arabs on the occupied Spanish soil. It enjoyed a brief period of independence as a taifa state from 1035-1058. It was named al-Jazirah al-Khadra' after the offshore Isla Verde; the modern name is derived from this original Arabic name.
After many centuries of Muslim rule, the tide of the reconquista arrived at Algeciras. In July 1309 Ferdinand IV of Castile laid siege to Algeciras as well as Gibraltar. The latter fell into Christian hands, but Muslim Algeciras held on for the following three decades, until Alfonso XI of Castile resumed its siege.
Juan Nunez de Lara, Juan Manuel, Pedro Fernández de Castro, Juan Alfonso de la Cerda, lord of Gibraleón all participated in the siege, as did knights from France, England and Germany, and even King Philip III of Navarre, king consort of Navarra, who came accompanied by 100 horsemen and 300 infantry.
In March 1344, after several years of siege, Algeciras surrendered.
The city was, however, retaken by the Moors in 1368 - but was destroyed on the orders of Muhammed V of Granada. The site was subsequently abandoned.
Algeciras was refounded in 1704 by refugees from Gibraltar following the territory's capture by Anglo-Dutch forces in the War of the Spanish Succession. It was rebuilt on its present rectangular plan by Charles III of Spain in 1760.
In July 1801, the French and Spanish navies fought the British Royal Navy offshore in the Battle of Algeciras, which ended in a British victory.
The city hosted the Algeciras Conference in 1906, an international forum to discuss the future of Morocco which was held in the Casa Consistorial (town hall).
In July 1942 Italian frogmen set up in a secret base in the Italian tanker Olterra, which was interned in Algeciras, in order to attack shipping in Gibraltar.
Port of Algeciras in recent years it has become a significant tourist destination, with popular day trips to Tarifa to see bird migrations, to Gibraltar to see the territory's sights and culture, and to the Bay of Gibraltar on whale watching excursions.
Algeciras is primarily and unashamedly a port and industrial centre, sprawling round the far side of the bay to Gibraltar. When Franco closed the border with "the Rock" at the nearby La Linea, it was Algeciras that he decided to develop to absorb the Spanish workers who used to be employed in the British naval dockyards and in order to break the area's dependence on Gibraltar.
It is an industrial city that supports the large deep water container port and nearby oil refinery. In the port area there are many Moroccans in transit, particularly during July and August when migrant workers return home for their holidays from their work in France, Holland and Belgium.
As a consequence, there is a strong Arab influence here with many of the signs in Arabic as well as Spanish while, in the backstreets, you can find several traditional tea shops which specialise in the traditional Moroccan mint tea. Algeciras may not be a beautiful city but it does have a gritty individuality about it and, unlike some of the Costa resorts, is a very genuine place with a real port atmosphere.
There are lots of reasonably priced restaurants to try - several with terrific views of the nearby Rock of Gibraltar. Those that find the time to wander will fine quiet parks and tree lined plazas almost hidden away from the rushing travellers.