Rock of Gibraltar

The Rock of Gibraltar is a monolithic limestone promontory rising about 426 meters at the southern tip of the Iberian Peninsula, overlooking the Strait of Gibraltar, formed from a thick sequence of Jurassic-age limestone, laid down roughly 200 to 145 million years ago on an ancient seabed and later thrust upward and tilted steeply by the tectonic collision between the African and Eurasian plates that also raised the surrounding mountains of southern Spain and northern Morocco. Its dramatic near-vertical north face is a fault scarp, exposed where compressional faulting during this mountain-building episode raised the limestone block sharply relative to the adjoining land, and the rock's interior has since been extensively hollowed by karst dissolution, honeycombing it with natural caves such as St Michael's Cave. Long recognized as one of the mythical Pillars of Hercules marking the western edge of the ancient world, the Rock remains a defining structural landmark of the strait separating Europe from Africa.