The northern boundary of the African Arab world has also fluttered briefly in the other direction, first through the Crusades and later through the imperial involvement of France, Britain, Spain, and Italy. Another visitor from northern shores, Turkey, controlled the east of the region for centuries, though not as a colonizer. Spain still maintains two small enclaves, Ceuta and Melilla (called "Morocco Espanol"), along the otherwise Moroccan coast. Overall this wave has ebbed, though like the Arab expansion north it has left its mark. The proximity of North Africa to Europe has always encouraged interaction, and this continues with Arab immigration to Europe and European interest in the Arab countries today. However, population centers and the physical fact of the sea keeps this boundary of the Arab World settled on the Mediterranean coastline.