Rock of Gibraltar may have originated from an escape of North African animals transported to Spain; it is also possible that the original Gibraltar macaques are a remnant of populations that are known to have spread throughout Southern Europe during the Pliocene, up to 5.5 million years ago. Some animals of the Rock have been reintroduced by the Alameda Wildlife Conservation Park who have three Barbary macaques. The Rock of Gibraltar, at the head of the Strait, is a prominent headland, which accumulates migrating birds during the passage periods. The vegetation on the Rock, unique in southern Iberia, provides a temporary home for
Footpaths of Gibraltar and across the Bay towards Algeciras. The area of the Rock through which the path passes is one of the richest in Gibraltar for flora and fauna. The start of the path is relatively sparsely vegetated and includes species such as White Asparagus, Common Asphodel, Germander and Esparto Grass. Its later sections proceed through dense vegetation that is typical of Mediterranean maquis shrubland – a widespread biome in southern Europe that consists of densely growing evergreen shrubs adapted to resist droughts. The trees along the path are predominantly olives. These have all grown since the Great Siege of Gibraltar (1779–83)