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
Rock of Gibraltar time, dried up during the Messinian salinity crisis. The Atlantic Ocean then broke through the Strait of Gibraltar, and the resultant flooding created the Mediterranean Sea. The Rock forms part of the Betic Cordillera, a mountain range that dominates south-eastern Iberia. Today, the Rock of Gibraltar forms a peninsula jutting out into the Strait of Gibraltar from the southern coast of Spain. The promontory is linked to the continent by means of a sandy tombolo with a maximum elevation of . To the north, the Rock rises vertically from sea level up to at Rock Gun Battery. The Rock's highest